Common Weakness Enumeration

CWE-22

Weakness Allowed-with-Review

Improper Limitation of a Pathname to a Restricted Directory

Abstraction: Base · Status: Stable

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Many file operations are intended to take place within a restricted directory. By using special elements such as ".." and "/" separators, attackers can escape outside of the restricted location to access files or directories that are elsewhere on the system. One of the most common special elements is the "../" sequence, which in most modern operating systems is interpreted as the parent directory of the current location. This is referred to as relative path traversal. Path traversal also covers the use of absolute pathnames such as "/usr/local/bin" to access unexpected files. This is referred to as absolute path traversal.

Mapping guidance

This CWE entry might have children that would be more appropriate.

Examine children of this entry to see if there is a better fit. Consider children such as CWE-23 (or its descendants) for relative path traversal, or CWE-36 for absolute path traversal.

Relationships and members
ChildOf: CWE-706 · View CWE-1000
ChildOf: CWE-706 · View CWE-1003
CanPrecede: CWE-668 · View CWE-1000
Modes of introduction
Implementation
Detection methods

Automated Static Analysis

Automated techniques can find areas where path traversal weaknesses exist. However, tuning or customization may be required to remove or de-prioritize path-traversal problems that are only exploitable by the product's administrator - or other privileged users - and thus potentially valid behavior or, at worst, a bug instead of a vulnerability.

Effectiveness: High

Manual Static Analysis

Manual white box techniques may be able to provide sufficient code coverage and reduction of false positives if all file access operations can be assessed within limited time constraints.

Effectiveness: High

Automated Static Analysis - Binary or Bytecode

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

Cost effective for partial coverage:

Binary Weakness Analysis - including disassembler + source code weakness analysis

Effectiveness: High

Manual Static Analysis - Binary or Bytecode

According to SOAR [REF-1479], the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: High

Dynamic Analysis with Manual Results Interpretation

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Fuzz Tester

Framework-based Fuzzer

Effectiveness: High

Manual Static Analysis - Source Code

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Manual Source Code Review (not inspections)

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: High

Architecture or Design Review

According to SOAR [REF-1479], the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Notes

Other

In many programming languages, the injection of a null byte (the 0 or NUL) may allow an attacker to truncate a generated filename to apply to a wider range of files. For example, the product may add ".txt" to any pathname, thus limiting the attacker to text files, but a null injection may effectively remove this restriction.

Relationship

Pathname equivalence can be regarded as a type of canonicalization error.

Relationship

Some pathname equivalence issues are not directly related to directory traversal, rather are used to bypass security-relevant checks for whether a file/directory can be accessed by the attacker (e.g. a trailing "/" on a filename could bypass access rules that don't expect a trailing /, causing a server to provide the file when it normally would not).

Terminology

Like other weaknesses, terminology is often based on the types of manipulations used, instead of the underlying weaknesses. Some people use "directory traversal" only to refer to the injection of ".." and equivalent sequences whose specific meaning is to traverse directories.

Other variants like "absolute pathname" and "drive letter" have the *effect* of directory traversal, but some people may not call it such, since it doesn't involve ".." or equivalent.

Research Gap

Many variants of path traversal attacks are probably under-studied with respect to root cause. CWE-790 and CWE-182 begin to cover part of this gap.

Research Gap

Incomplete diagnosis or reporting of vulnerabilities can make it difficult to know which variant is affected. For example, a researcher might say that "..\" is vulnerable, but not test "../" which may also be vulnerable.

Any combination of directory separators ("/", "\", etc.) and numbers of "." (e.g. "....") can produce unique variants; for example, the "//../" variant is not listed (CVE-2004-0325). See this entry's children and lower-level descendants.

Content history
Submission: PLOVER · 2006-07-19 · CWE Draft 3
Contribution: Nick Johnston · 2022-07-11 · CWE 4.9

Identified weakness in Perl demonstrative example

Contribution: Abhi Balakrishnan · 2024-02-29 · CWE 4.15

Provided diagram to improve CWE usability

Contribution: Drew Buttner · MITRE · 2024-11-01 · CWE 4.16

Identified weakness in "good code" for Python demonstrative example

Contribution: Affan Ahmed · 2025-02-08 · CWE 4.20

Provided a demonstrative example in PHP

Modification: Eric Dalci · Cigital · 2008-07-01 · CWE 1.0

updated Potential_Mitigations, Time_of_Introduction

Modification: · Veracode · 2008-08-15 · CWE 1.0

Suggested OWASP Top Ten 2004 mapping

Modification: CWE Content Team · MITRE · 2008-09-08 · CWE 1.0

updated Alternate_Terms, Relationships, Other_Notes, Relationship_Notes, Relevant_Properties, Taxonomy_Mappings, Weakness_Ordinalities

Modification: CWE Content Team · MITRE · 2008-10-14 · CWE 1.0.1

updated Description

Modification: CWE Content Team · MITRE · 2008-11-24 · CWE 1.1

updated Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2009-07-27 · CWE 1.5

updated Potential_Mitigations

Modification: CWE Content Team · MITRE · 2010-02-16 · CWE 1.8

updated Alternate_Terms, Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Description, Detection_Factors, Likelihood_of_Exploit, Name, Observed_Examples, Other_Notes, Potential_Mitigations, References, Related_Attack_Patterns, Relationship_Notes, Relationships, Research_Gaps, Taxonomy_Mappings, Terminology_Notes, Time_of_Introduction, Weakness_Ordinalities

Modification: CWE Content Team · MITRE · 2010-06-21 · CWE 1.9

updated Common_Consequences, Demonstrative_Examples, Description, Detection_Factors, Potential_Mitigations, References, Relationships

Modification: CWE Content Team · MITRE · 2010-09-27 · CWE 1.10

updated Potential_Mitigations

Modification: CWE Content Team · MITRE · 2010-12-13 · CWE 1.11

updated Potential_Mitigations

Modification: CWE Content Team · MITRE · 2011-03-29 · CWE 1.12

updated Potential_Mitigations

Modification: CWE Content Team · MITRE · 2011-06-27 · CWE 2.0

updated Relationships

Modification: CWE Content Team · MITRE · 2011-09-13 · CWE 2.1

updated Potential_Mitigations, References, Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2012-05-11 · CWE 2.2

updated Demonstrative_Examples, References, Relationships

Modification: CWE Content Team · MITRE · 2012-10-30 · CWE 2.3

updated Potential_Mitigations

Modification: CWE Content Team · MITRE · 2013-02-21 · CWE 2.4

updated Observed_Examples

Modification: CWE Content Team · MITRE · 2013-07-17 · CWE 2.5

updated Related_Attack_Patterns, Relationships

Modification: CWE Content Team · MITRE · 2014-06-23 · CWE 2.7

updated Other_Notes, Research_Gaps

Modification: CWE Content Team · MITRE · 2014-07-30 · CWE 2.8

updated Detection_Factors, Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2015-12-07 · CWE 2.9

updated Relationships

Modification: CWE Content Team · MITRE · 2017-01-19 · CWE 2.10

updated Related_Attack_Patterns

Modification: CWE Content Team · MITRE · 2017-05-03 · CWE 2.11

updated Demonstrative_Examples

Modification: CWE Content Team · MITRE · 2017-11-08 · CWE 3.0

updated Affected_Resources, Causal_Nature, Likelihood_of_Exploit, References, Relationships, Relevant_Properties, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2018-03-27 · CWE 3.1

updated References, Relationships

Modification: CWE Content Team · MITRE · 2019-01-03 · CWE 3.2

updated References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2019-06-20 · CWE 3.3

updated Related_Attack_Patterns, Relationships, Type

Modification: CWE Content Team · MITRE · 2019-09-19 · CWE 3.4

updated Relationships

Modification: CWE Content Team · MITRE · 2020-02-24 · CWE 4.0

updated Potential_Mitigations, Relationships

Modification: CWE Content Team · MITRE · 2020-06-25 · CWE 4.1

updated Demonstrative_Examples, Potential_Mitigations

Modification: CWE Content Team · MITRE · 2020-08-20 · CWE 4.2

updated Relationships

Modification: CWE Content Team · MITRE · 2020-12-10 · CWE 4.3

updated Potential_Mitigations, Relationships

Modification: CWE Content Team · MITRE · 2021-03-15 · CWE 4.4

updated Demonstrative_Examples, Relationships

Modification: CWE Content Team · MITRE · 2021-07-20 · CWE 4.5

updated Relationships

Modification: CWE Content Team · MITRE · 2021-10-28 · CWE 4.6

updated Observed_Examples, Relationships

Modification: CWE Content Team · MITRE · 2022-06-28 · CWE 4.8

updated Observed_Examples, Relationships

Modification: CWE Content Team · MITRE · 2022-10-13 · CWE 4.9

updated Observed_Examples, References

Modification: CWE Content Team · MITRE · 2023-01-31 · CWE 4.10

updated Common_Consequences, Description, Detection_Factors

Modification: CWE Content Team · MITRE · 2023-04-27 · CWE 4.11

updated Demonstrative_Examples, References, Relationships, Time_of_Introduction

Modification: CWE Content Team · MITRE · 2023-06-29 · CWE 4.12

updated Mapping_Notes, Relationships

Modification: CWE Content Team · MITRE · 2023-10-26 · CWE 4.13

updated Observed_Examples

Modification: CWE Content Team · MITRE · 2024-07-16 · CWE 4.15

updated Common_Consequences, Description, Diagram, Observed_Examples, Other_Notes, References

Modification: CWE Content Team · MITRE · 2024-11-19 · CWE 4.16

updated Demonstrative_Examples, Relationships

Modification: CWE Content Team · MITRE · 2025-04-03 · CWE 4.17

updated Relationships

Modification: CWE Content Team · MITRE · 2025-09-09 · CWE 4.18

updated Applicable_Platforms, Detection_Factors, Observed_Examples, Potential_Mitigations, References

Modification: CWE Content Team · MITRE · 2025-12-11 · CWE 4.19

updated Mapping_Notes, Relationships

Modification: CWE Content Team · MITRE · 2026-04-30 · CWE 4.20

updated Alternate_Terms, Applicable_Platforms, Demonstrative_Examples, Relationships

Modification: CWE Content Team · MITRE · 2026-10-28 · CWE 5.0

updated Applicable_Platforms, Common_Consequences, Name, References, Relationships, Taxonomy_Mappings

16185 vulnerabilities reference this CWE, most recent first.

GHSA-79HX-3FP8-HJ66

Vulnerability from github – Published: 2025-09-17 20:11 – Updated: 2025-09-26 16:18
VLAI
Summary
DragonFly vulnerable to arbitrary file read and write on a peer machine
Details

Impact

A peer exposes the gRPC API and HTTP API for consumption by other peers. These APIs allow peers to send requests that force the recipient peer to create files in arbitrary file system locations, and to read arbitrary files. This allows peers to steal other peers’ secret data and to gain remote code execution (RCE) capabilities on the peer’s machine.

file, err := os.OpenFile(t.DataFilePath, os.O_RDWR, defaultFileMode)
if err != nil {
       return 0, err
}
defer file.Close()
if _, err = file.Seek(req.Range.Start, io.SeekStart); err != nil {
       return 0, err
}
n, err := io.Copy(file, io.LimitReader(req.Reader, req.Range.Length))

Patches

  • Dragonfy v2.1.0 and above.

Workarounds

There are no effective workarounds, beyond upgrading.

References

A third party security audit was performed by Trail of Bits, you can see the full report.

If you have any questions or comments about this advisory, please email us at dragonfly-maintainers@googlegroups.com.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/dragonflyoss/dragonfly"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "d7y.io/dragonfly/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-59352"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-202",
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-09-17T20:11:13Z",
    "nvd_published_at": "2025-09-17T20:15:37Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\nA peer exposes the gRPC API and HTTP API for consumption by other peers. These APIs allow peers to send requests that force the recipient peer to create files in arbitrary file system locations, and to read arbitrary files. This allows peers to steal other peers\u2019 secret data and to gain remote code execution (RCE) capabilities on the peer\u2019s machine.\n\n```golang\nfile, err := os.OpenFile(t.DataFilePath, os.O_RDWR, defaultFileMode)\nif err != nil {\n       return 0, err\n}\ndefer file.Close()\nif _, err = file.Seek(req.Range.Start, io.SeekStart); err != nil {\n       return 0, err\n}\nn, err := io.Copy(file, io.LimitReader(req.Reader, req.Range.Length))\n```\n\n### Patches\n\n- Dragonfy v2.1.0 and above.\n\n### Workarounds\n\nThere are no effective workarounds, beyond upgrading.\n\n### References\n\nA third party security audit was performed by Trail of Bits, you can see the [full report](https://github.com/dragonflyoss/dragonfly/blob/main/docs/security/dragonfly-comprehensive-report-2023.pdf).\n\nIf you have any questions or comments about this advisory, please email us at [dragonfly-maintainers@googlegroups.com](mailto:dragonfly-maintainers@googlegroups.com).",
  "id": "GHSA-79hx-3fp8-hj66",
  "modified": "2025-09-26T16:18:51Z",
  "published": "2025-09-17T20:11:13Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/dragonflyoss/dragonfly/security/advisories/GHSA-79hx-3fp8-hj66"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-59352"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/dragonflyoss/dragonfly"
    },
    {
      "type": "WEB",
      "url": "https://github.com/dragonflyoss/dragonfly/blob/main/docs/security/dragonfly-comprehensive-report-2023.pdf"
    },
    {
      "type": "WEB",
      "url": "https://pkg.go.dev/vuln/GO-2025-3961"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "DragonFly vulnerable to arbitrary file read and write on a peer machine"
}

GHSA-79JF-625M-7XJF

Vulnerability from github – Published: 2022-04-29 03:00 – Updated: 2022-04-29 03:00
VLAI
Details

Directory traversal vulnerability in the map feature (tiki-map.phtml) in Tiki CMS/Groupware (TikiWiki) 1.8.1 and earlier allows remote attackers to determine the existence of arbitrary files via .. (dot dot) sequences in the mapfile parameter.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2004-1927"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2004-04-11T04:00:00Z",
    "severity": "MODERATE"
  },
  "details": "Directory traversal vulnerability in the map feature (tiki-map.phtml) in Tiki CMS/Groupware (TikiWiki) 1.8.1 and earlier allows remote attackers to determine the existence of arbitrary files via .. (dot dot) sequences in the mapfile parameter.",
  "id": "GHSA-79jf-625m-7xjf",
  "modified": "2022-04-29T03:00:28Z",
  "published": "2022-04-29T03:00:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2004-1927"
    },
    {
      "type": "WEB",
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/15848"
    },
    {
      "type": "WEB",
      "url": "http://marc.info/?l=bugtraq\u0026m=108180073206947\u0026w=2"
    },
    {
      "type": "WEB",
      "url": "http://secunia.com/advisories/11344"
    },
    {
      "type": "WEB",
      "url": "http://tikiwiki.org/tiki-read_article.php?articleId=66"
    },
    {
      "type": "WEB",
      "url": "http://www.securityfocus.com/bid/10100"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-79MG-HFRX-5889

Vulnerability from github – Published: 2025-02-18 06:35 – Updated: 2026-04-08 18:33
VLAI
Details

The Actionwear products sync plugin for WordPress is vulnerable to Full Path Disclosure in all versions up to, and including, 2.3.0. This is due the composer-setup.php file being publicly accessible with 'display_errors' set to true. This makes it possible for unauthenticated attackers to retrieve the full path of the web application, which can be used to aid other attacks. The information displayed is not useful on its own, and requires another vulnerability to be present for damage to an affected website.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2024-13535"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-209",
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-18T05:15:12Z",
    "severity": "MODERATE"
  },
  "details": "The Actionwear products sync plugin for WordPress is vulnerable to Full Path Disclosure in all versions up to, and including, 2.3.0. This is due the composer-setup.php file being publicly accessible with \u0027display_errors\u0027 set to true. This makes it possible for unauthenticated attackers to retrieve the full path of the web application, which can be used to aid other attacks. The information displayed is not useful on its own, and requires another vulnerability to be present for damage to an affected website.",
  "id": "GHSA-79mg-hfrx-5889",
  "modified": "2026-04-08T18:33:48Z",
  "published": "2025-02-18T06:35:38Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-13535"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/actionwear-products-sync/trunk/composer-setup.php"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/changeset?sfp_email=\u0026sfph_mail=\u0026reponame=\u0026old=3241824%40actionwear-products-sync\u0026new=3241824%40actionwear-products-sync\u0026sfp_email=\u0026sfph_mail="
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/6dbf9689-c812-4b7c-9df3-c4639aae3357?source=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-79P8-4CWQ-RHQH

Vulnerability from github – Published: 2018-07-23 20:40 – Updated: 2023-09-05 23:24
VLAI
Summary
Directory Traversal in jn_jj_server
Details

Affected versions of jn_jj_server resolve relative file paths, resulting in a directory traversal vulnerability. A malicious actor can use this vulnerability to access files outside of the intended directory root, which may result in the disclosure of private files on the vulnerable system.

Example request:

GET /../../../../../../../../../../etc/passwd HTTP/1.1
host:foo

Recommendation

No patch is available for this vulnerability.

It is recommended that the package is only used for local development, and if the functionality is needed for production, a different package is used instead.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "jn_jj_server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "0.0.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2017-16210"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2020-06-16T21:22:18Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "Affected versions of `jn_jj_server` resolve relative file paths, resulting in a directory traversal vulnerability. A malicious actor can use this vulnerability to access files outside of the intended directory root, which may result in the disclosure of private files on the vulnerable system.\n\n**Example request:**\n```http\nGET /../../../../../../../../../../etc/passwd HTTP/1.1\nhost:foo\n```\n\n\n## Recommendation\n\nNo patch is available for this vulnerability.\n\nIt is recommended that the package is only used for local development, and if the functionality is needed for production, a different package is used instead.",
  "id": "GHSA-79p8-4cwq-rhqh",
  "modified": "2023-09-05T23:24:25Z",
  "published": "2018-07-23T20:40:07Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2017-16210"
    },
    {
      "type": "WEB",
      "url": "https://github.com/JacksonGL/NPM-Vuln-PoC/blob/master/directory-traversal/jn_jj_server"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-79p8-4cwq-rhqh"
    },
    {
      "type": "WEB",
      "url": "https://www.npmjs.com/advisories/424"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [],
  "summary": "Directory Traversal in jn_jj_server"
}

GHSA-79PH-745M-6WXQ

Vulnerability from github – Published: 2026-06-16 17:35 – Updated: 2026-07-20 13:41
VLAI
Summary
Langflow: Path Traversal in Knowledge Bases API via Creation Endpoint
Details

Summary

Langflow is vulnerable to Path Traversal in the Knowledge Bases API (POST /api/v1/knowledge_bases). This occurs because user-supplied knowledge base names are used directly to create file paths without proper sanitization or containment checks. An authenticated attacker can exploit this flaw to create directories and write files anywhere on the server's filesystem.

Details

The vulnerability exists in the create_knowledge_base function within src/backend/base/langflow/api/v1/knowledge_bases.py.

This function constructs file paths directly from the user-supplied name field without sanitization. The value is concatenated with the user's base directory and passed directly to kb_path.mkdir(). Immediately following the directory creation, the application writes embedding_metadata.json and schema.json into this attacker-controlled path.

PoC (Proof of Concept)

For the Create endpoint, an attacker can supply traversal sequences or absolute paths in the name field:

../victim_user/evil_kb or /tmp/pwned

This forces kb_path.mkdir() to create directories and write specific application files (embedding_metadata.json and schema.json) at any reachable path on the server.

Impact

Any Langflow instance exposing this endpoint to authenticated users is vulnerable. This exposes the server to: * Cross-user data compromise: Creation of directories and files within another tenant's knowledge base space. * Arbitrary filesystem manipulation: Directory creation at any path on the server where the application has write permissions (e.g., /app/data). * Data overwrite: Overwriting existing embedding_metadata.json and schema.json files in attacker-targeted paths, potentially corrupting existing knowledge bases.

Fixes

The issue was addressed in PR #12337. The fix introduces the _validate_kb_path_containment() helper function, which uses Path.is_relative_to() instead of startswith() to enforce strict path boundaries and prevent prefix-ambiguity bugs. This helper is applied before any filesystem operations. Regression tests were added to verify that traversal payloads return a 403 Forbidden.

Acknowledgements

Thanks to the security researchers who responsibly disclosed this vulnerability: * @ddlxstudio * @nekros1xx

Show details on source website

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.8.4"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "langflow"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.9.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-42867"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-16T17:35:09Z",
    "nvd_published_at": "2026-06-23T17:16:58Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\nLangflow is vulnerable to Path Traversal in the Knowledge Bases API (`POST /api/v1/knowledge_bases`). This occurs because user-supplied knowledge base names are used directly to create file paths without proper sanitization or containment checks. An authenticated attacker can exploit this flaw to create directories and write files anywhere on the server\u0027s filesystem.\n\n## Details\nThe vulnerability exists in the `create_knowledge_base` function within `src/backend/base/langflow/api/v1/knowledge_bases.py`. \n\nThis function constructs file paths directly from the user-supplied `name` field without sanitization. The value is concatenated with the user\u0027s base directory and passed directly to `kb_path.mkdir()`. Immediately following the directory creation, the application writes `embedding_metadata.json` and `schema.json` into this attacker-controlled path.\n\n## PoC (Proof of Concept)\nFor the **Create** endpoint, an attacker can supply traversal sequences or absolute paths in the `name` field:\n\n`../victim_user/evil_kb`\nor\n`/tmp/pwned`\n\nThis forces `kb_path.mkdir()` to create directories and write specific application files (`embedding_metadata.json` and `schema.json`) at any reachable path on the server.\n\n## Impact\nAny Langflow instance exposing this endpoint to authenticated users is vulnerable. This exposes the server to:\n* **Cross-user data compromise:** Creation of directories and files within another tenant\u0027s knowledge base space.\n* **Arbitrary filesystem manipulation:** Directory creation at any path on the server where the application has write permissions (e.g., `/app/data`).\n* **Data overwrite:** Overwriting existing `embedding_metadata.json` and `schema.json` files in attacker-targeted paths, potentially corrupting existing knowledge bases.\n\n## Fixes\nThe issue was addressed in **PR #12337**. The fix introduces the `_validate_kb_path_containment()` helper function, which uses `Path.is_relative_to()` instead of `startswith()` to enforce strict path boundaries and prevent prefix-ambiguity bugs. This helper is applied before any filesystem operations. Regression tests were added to verify that traversal payloads return a `403 Forbidden`.\n\n## Acknowledgements\nThanks to the security researchers who responsibly disclosed this vulnerability:\n* @ddlxstudio\n* @nekros1xx",
  "id": "GHSA-79ph-745m-6wxq",
  "modified": "2026-07-20T13:41:52Z",
  "published": "2026-06-16T17:35:09Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/langflow-ai/langflow/security/advisories/GHSA-79ph-745m-6wxq"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42867"
    },
    {
      "type": "WEB",
      "url": "https://github.com/langflow-ai/langflow/pull/12337"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-79ph-745m-6wxq"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/langflow-ai/langflow"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/langflow/PYSEC-2026-2566.yaml"
    },
    {
      "type": "WEB",
      "url": "https://pypi.org/project/langflow"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Langflow: Path Traversal in Knowledge Bases API via Creation Endpoint"
}

GHSA-79PP-3MFJ-FP8J

Vulnerability from github – Published: 2022-05-02 03:28 – Updated: 2022-05-02 03:28
VLAI
Details

Multiple directory traversal vulnerabilities in index.php in Catviz 0.4.0 Beta 1 allow remote attackers to read arbitrary files via a .. (dot dot) in the (1) webpages_form or (2) userman_form parameter.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2009-1748"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2009-05-22T11:52:00Z",
    "severity": "HIGH"
  },
  "details": "Multiple directory traversal vulnerabilities in index.php in Catviz 0.4.0 Beta 1 allow remote attackers to read arbitrary files via a .. (dot dot) in the (1) webpages_form or (2) userman_form parameter.",
  "id": "GHSA-79pp-3mfj-fp8j",
  "modified": "2022-05-02T03:28:14Z",
  "published": "2022-05-02T03:28:14Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2009-1748"
    },
    {
      "type": "WEB",
      "url": "https://www.exploit-db.com/exploits/8745"
    },
    {
      "type": "WEB",
      "url": "http://osvdb.org/54657"
    },
    {
      "type": "WEB",
      "url": "http://www.securityfocus.com/bid/35042"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-79Q7-7HWR-QJ8F

Vulnerability from github – Published: 2022-05-01 23:28 – Updated: 2022-05-01 23:28
VLAI
Details

Absolute path traversal vulnerability in index.php in Million Dollar Script 2.0.14 allows remote attackers to read arbitrary files via encoded "/" (%2F) sequences in the link parameter.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2008-0156"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2008-01-09T00:46:00Z",
    "severity": "MODERATE"
  },
  "details": "Absolute path traversal vulnerability in index.php in Million Dollar Script 2.0.14 allows remote attackers to read arbitrary files via encoded \"/\" (%2F) sequences in the link parameter.",
  "id": "GHSA-79q7-7hwr-qj8f",
  "modified": "2022-05-01T23:28:01Z",
  "published": "2022-05-01T23:28:01Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2008-0156"
    },
    {
      "type": "WEB",
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/39492"
    },
    {
      "type": "WEB",
      "url": "http://securityreason.com/securityalert/3524"
    },
    {
      "type": "WEB",
      "url": "http://www.securityfocus.com/archive/1/485882/100/0/threaded"
    },
    {
      "type": "WEB",
      "url": "http://www.securityfocus.com/bid/27174"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-79QF-VQGC-7XX3

Vulnerability from github – Published: 2026-09-02 14:55 – Updated: 2026-11-02 23:00
VLAI
Summary
ApostropheCMS: Arbitrary file read via import-export attachment-name path traversal
Details

Summary

The @apostrophecms/import-export module reconstructs the on-disk source path of every imported attachment from JSON metadata contained in the uploaded archive.

The archive carries an aposAttachments.json file whose name and extension fields are concatenated into a filesystem path with no traversal check. The zip-slip guard that the module applies during tar extraction validates tar entry names only and does not cover this second path, which is built after extraction.

The file at the resulting path is read and copied into the public uploads directory, then served over HTTP without authentication. A ../ sequence in name makes the module read a file outside the extraction directory and publish it at an anonymous URL.

Result: an authenticated contributor reads any file on the host whose name ends in an allowlisted extension (other users' uploaded documents, text or CSV dumps, PDFs) by importing a crafted archive and fetching the planted attachment anonymously.

Affected

apostrophecms/apostrophe with the @apostrophecms/import-export module installed and registered. Module version 3.6.1, tested against Apostrophe 4.31.0 (monorepo HEAD 4d478d9). Requires an account with the contributor role or higher; guest and anonymous requests are rejected. The module is not part of the default starter kit, so sites that never installed it are not affected. Files whose real name lacks an accepted file-group extension are not reachable.

Root cause

The import parser builds each attachment's source path by concatenating attacker-controlled JSON fields: lib/formats/gzip.js:46 sets file.path = path.join(attachmentFilesPath, ${attachment._id}-${attachment.name}.${attachment.extension}) from the aposAttachments.json entries in the uploaded archive. That path flows unchanged through lib/methods/import.js:832 (insertAttachments) into lib/methods/import.js:1074 (attachment.insert), where uploadfs copies the referenced file into the public uploads directory served by express.static. The archive's only traversal guard, lib/formats/gzip.js:143 (if (name.includes('../'))), validates tar entry names during extraction and never inspects the name/extension values used to construct the read path, so a name of ../../../../../../tmp/secret escapes attachmentFilesPath. Reaching the sink requires only an authenticated session (lib/methods/import.js:71), view permission on the target type (lib/methods/index.js:54), and the upload-attachment permission enforced at modules/@apostrophecms/attachment/index.js:442, which the built-in contributor role holds. The trailing .${extension} is appended and checked against the file-group allowlist in modules/@apostrophecms/attachment/index.js (getFileGroup), so the target file's real name must end in an accepted extension (txt, csv, pdf, xls, doc, svg, and similar).

Reproduction

Apostrophe 4.31.0 starter-kit-essentials, MongoDB, default roles, @apostrophecms/import-export 3.6.1 installed, local uploadfs backend.

  1. Place a secret file outside the upload tree with an allowlisted extension.
$ cat /tmp/apos_victim_secret.txt
TOP-SECRET DB DUMP
DB_PASSWORD=Pr0d-Secret-9981
API_KEY=sk_live_victim_abcdef
  1. Build a gzip archive whose aposAttachments.json points the attachment name at that file through traversal (aposDocs.json is []).
[{"_id":"evilatt0001","name":"../../../../../../../../../../../../tmp/apos_victim_secret","extension":"txt","title":"loot","docIds":[],"crops":[]}]
  1. As a contributor, import the archive through the module's import action (POST /api/v1/@apostrophecms/<type>/import-export-import), then fetch the created attachment with no session.
$ curl -i http://localhost:3500/uploads/attachments/evilatt0001-apos-victim-secret.txt
HTTP/1.1 200 OK
Content-Type: text/plain; charset=UTF-8

TOP-SECRET DB DUMP
DB_PASSWORD=Pr0d-Secret-9981
API_KEY=sk_live_victim_abcdef

Live-verified: a contributor-driven import reads /tmp/apos_victim_secret.txt (outside the extraction directory) and serves it at an anonymous URL; the same import run as a guest is rejected at the upload-attachment check (modules/@apostrophecms/attachment/index.js:442).

Impact

  • Read of arbitrary host files whose real name ends in an allowlisted extension (txt, csv, pdf, xls, doc, svg, and similar).
  • Disclosure of other users' uploaded documents and any allowlisted-extension file readable by the Node process.
  • The exfiltration target is copied to a public, unauthenticated URL.
  • Triggered by the contributor role in a single import, no admin interaction.

Credit

Jan Kahmen, turingpoint (jan@turingpoint.de)

Show details on source website

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.6.1"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@apostrophecms/import-export"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.6.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-63667"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-02T14:55:47Z",
    "nvd_published_at": "2026-08-17T20:16:44Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nThe `@apostrophecms/import-export` module reconstructs the on-disk source path of every imported attachment from JSON metadata contained in the uploaded archive.\n\nThe archive carries an `aposAttachments.json` file whose `name` and `extension` fields are concatenated into a filesystem path with no traversal check. The zip-slip guard that the module applies during tar extraction validates tar entry names only and does not cover this second path, which is built after extraction.\n\nThe file at the resulting path is read and copied into the public uploads directory, then served over HTTP without authentication. A `../` sequence in `name` makes the module read a file outside the extraction directory and publish it at an anonymous URL.\n\nResult: an authenticated contributor reads any file on the host whose name ends in an allowlisted extension (other users\u0027 uploaded documents, text or CSV dumps, PDFs) by importing a crafted archive and fetching the planted attachment anonymously.\n\n## Affected\n\napostrophecms/apostrophe with the `@apostrophecms/import-export` module installed and registered. Module version 3.6.1, tested against Apostrophe 4.31.0 (monorepo HEAD 4d478d9). Requires an account with the contributor role or higher; guest and anonymous requests are rejected. The module is not part of the default starter kit, so sites that never installed it are not affected. Files whose real name lacks an accepted file-group extension are not reachable.\n\n## Root cause\n\nThe import parser builds each attachment\u0027s source path by concatenating attacker-controlled JSON fields: `lib/formats/gzip.js:46` sets `file.path = path.join(attachmentFilesPath, ${attachment._id}-${attachment.name}.${attachment.extension})` from the `aposAttachments.json` entries in the uploaded archive. That path flows unchanged through `lib/methods/import.js:832` (`insertAttachments`) into `lib/methods/import.js:1074` (`attachment.insert`), where uploadfs copies the referenced file into the public uploads directory served by `express.static`. The archive\u0027s only traversal guard, `lib/formats/gzip.js:143` (`if (name.includes(\u0027../\u0027))`), validates tar entry names during extraction and never inspects the `name`/`extension` values used to construct the read path, so a `name` of `../../../../../../tmp/secret` escapes `attachmentFilesPath`. Reaching the sink requires only an authenticated session (`lib/methods/import.js:71`), view permission on the target type (`lib/methods/index.js:54`), and the `upload-attachment` permission enforced at `modules/@apostrophecms/attachment/index.js:442`, which the built-in contributor role holds. The trailing `.${extension}` is appended and checked against the file-group allowlist in `modules/@apostrophecms/attachment/index.js` (`getFileGroup`), so the target file\u0027s real name must end in an accepted extension (txt, csv, pdf, xls, doc, svg, and similar).\n\n## Reproduction\n\nApostrophe 4.31.0 starter-kit-essentials, MongoDB, default roles, `@apostrophecms/import-export` 3.6.1 installed, local uploadfs backend.\n\n1. Place a secret file outside the upload tree with an allowlisted extension.\n\n```\n$ cat /tmp/apos_victim_secret.txt\nTOP-SECRET DB DUMP\nDB_PASSWORD=Pr0d-Secret-9981\nAPI_KEY=sk_live_victim_abcdef\n```\n\n2. Build a gzip archive whose `aposAttachments.json` points the attachment `name` at that file through traversal (`aposDocs.json` is `[]`).\n\n```\n[{\"_id\":\"evilatt0001\",\"name\":\"../../../../../../../../../../../../tmp/apos_victim_secret\",\"extension\":\"txt\",\"title\":\"loot\",\"docIds\":[],\"crops\":[]}]\n```\n\n3. As a contributor, import the archive through the module\u0027s import action (`POST /api/v1/@apostrophecms/\u003ctype\u003e/import-export-import`), then fetch the created attachment with no session.\n\n```\n$ curl -i http://localhost:3500/uploads/attachments/evilatt0001-apos-victim-secret.txt\nHTTP/1.1 200 OK\nContent-Type: text/plain; charset=UTF-8\n\nTOP-SECRET DB DUMP\nDB_PASSWORD=Pr0d-Secret-9981\nAPI_KEY=sk_live_victim_abcdef\n```\n\nLive-verified: a contributor-driven import reads `/tmp/apos_victim_secret.txt` (outside the extraction directory) and serves it at an anonymous URL; the same import run as a guest is rejected at the `upload-attachment` check (`modules/@apostrophecms/attachment/index.js:442`).\n\n## Impact\n\n- Read of arbitrary host files whose real name ends in an allowlisted extension (txt, csv, pdf, xls, doc, svg, and similar).\n- Disclosure of other users\u0027 uploaded documents and any allowlisted-extension file readable by the Node process.\n- The exfiltration target is copied to a public, unauthenticated URL.\n- Triggered by the contributor role in a single import, no admin interaction.\n\n## Credit\n\nJan Kahmen, [turingpoint](https://www.turingpoint.de) (jan@turingpoint.de)",
  "id": "GHSA-79qf-vqgc-7xx3",
  "modified": "2026-11-02T23:00:32Z",
  "published": "2026-09-02T14:55:47Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-79qf-vqgc-7xx3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63667"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apostrophecms/apostrophe/commit/87cccf44a23d09420875ca8a3765eb3db843836a"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/apostrophecms/apostrophe"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apostrophecms/apostrophe/discussions/5516"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ApostropheCMS: Arbitrary file read via import-export attachment-name path traversal"
}

GHSA-79R3-H45P-3C2X

Vulnerability from github – Published: 2024-05-17 09:31 – Updated: 2024-05-17 09:31
VLAI
Details

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in By Averta Shortcodes and extra features for Phlox theme allows PHP Local File Inclusion.This issue affects Shortcodes and extra features for Phlox theme: from n/a through 2.14.0.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2023-37888"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-05-17T07:15:57Z",
    "severity": "HIGH"
  },
  "details": "Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027) vulnerability in By Averta Shortcodes and extra features for Phlox theme allows PHP Local File Inclusion.This issue affects Shortcodes and extra features for Phlox theme: from n/a through 2.14.0.",
  "id": "GHSA-79r3-h45p-3c2x",
  "modified": "2024-05-17T09:31:00Z",
  "published": "2024-05-17T09:31:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-37888"
    },
    {
      "type": "WEB",
      "url": "https://patchstack.com/database/vulnerability/auxin-elements/wordpress-phlox-core-elements-plugin-2-14-0-unauthenticated-local-file-inclusion-vulnerability?_s_id=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-79RV-CC85-5QHH

Vulnerability from github – Published: 2022-05-24 17:37 – Updated: 2022-05-24 17:37
VLAI
Details

Multiple directory traversal vulnerabilities in TerraMaster TOS <= 4.2.06 allow remote authenticated attackers to read, edit or delete any file within the filesystem via the (1) filename parameter to /tos/index.php?editor/fileGet, Event parameter to /include/ajax/logtable.php, or opt parameter to /include/core/index.php.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2020-28187"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2020-12-24T15:15:00Z",
    "severity": "CRITICAL"
  },
  "details": "Multiple directory traversal vulnerabilities in TerraMaster TOS \u003c= 4.2.06 allow remote authenticated attackers to read, edit or delete any file within the filesystem via the (1) filename parameter to /tos/index.php?editor/fileGet, Event parameter to /include/ajax/logtable.php, or opt parameter to /include/core/index.php.",
  "id": "GHSA-79rv-cc85-5qhh",
  "modified": "2022-05-24T17:37:15Z",
  "published": "2022-05-24T17:37:15Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-28187"
    },
    {
      "type": "WEB",
      "url": "https://www.ihteam.net/advisory/terramaster-tos-multiple-vulnerabilities"
    },
    {
      "type": "WEB",
      "url": "https://www.terra-master.com"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

Mitigation MIT-5.1
Implementation

Strategy: Input Validation

  • Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434.
  • Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would be removed from the original string, but the remaining characters would still form the "../" string.
Mitigation MIT-15
Architecture and Design

For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

Mitigation MIT-20.1
Implementation

Strategy: Input Validation

  • Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
  • Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59). This includes:
  • realpath() in C
  • getCanonicalPath() in Java
  • GetFullPath() in ASP.NET
  • realpath() or abs_path() in Perl
  • realpath() in PHP
Mitigation MIT-4
Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].

Mitigation MIT-29
Operation

Strategy: Firewall

Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

Mitigation MIT-17
Architecture and Design Operation

Strategy: Environment Hardening

Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Mitigation MIT-21.1
Architecture and Design

Strategy: Enforcement by Conversion

  • When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
  • For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap [REF-185] provide this capability.
Mitigation MIT-22
Architecture and Design Operation

Strategy: Sandbox or Jail

  • Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software.
  • OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations.
  • This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.
  • Be careful to avoid CWE-243 and other weaknesses related to jails.
Mitigation MIT-34
Architecture and Design Operation

Strategy: Attack Surface Reduction

  • Store library, include, and utility files outside of the web document root, if possible. Otherwise, store them in a separate directory and use the web server's access control capabilities to prevent attackers from directly requesting them. One common practice is to define a fixed constant in each calling program, then check for the existence of the constant in the library/include file; if the constant does not exist, then the file was directly requested, and it can exit immediately.
  • This significantly reduces the chance of an attacker being able to bypass any protection mechanisms that are in the base program but not in the include files. It will also reduce the attack surface.
Mitigation MIT-39
Implementation
  • Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success.
  • If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files.
  • Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.
  • In the context of path traversal, error messages which disclose path information can help attackers craft the appropriate attack strings to move through the file system hierarchy.
Mitigation MIT-16
Operation Implementation

Strategy: Environment Hardening

When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.

CAPEC-126: Path Traversal

An adversary uses path manipulation methods to exploit insufficient input validation of a target to obtain access to data that should be not be retrievable by ordinary well-formed requests. A typical variety of this attack involves specifying a path to a desired file together with dot-dot-slash characters, resulting in the file access API or function traversing out of the intended directory structure and into the root file system. By replacing or modifying the expected path information the access function or API retrieves the file desired by the attacker. These attacks either involve the attacker providing a complete path to a targeted file or using control characters (e.g. path separators (/ or \) and/or dots (.)) to reach desired directories or files.

CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic

This attack targets the encoding of the URL combined with the encoding of the slash characters. An attacker can take advantage of the multiple ways of encoding a URL and abuse the interpretation of the URL. A URL may contain special character that need special syntax handling in order to be interpreted. Special characters are represented using a percentage character followed by two digits representing the octet code of the original character (%HEX-CODE). For instance US-ASCII space character would be represented with %20. This is often referred as escaped ending or percent-encoding. Since the server decodes the URL from the requests, it may restrict the access to some URL paths by validating and filtering out the URL requests it received. An attacker will try to craft an URL with a sequence of special characters which once interpreted by the server will be equivalent to a forbidden URL. It can be difficult to protect against this attack since the URL can contain other format of encoding such as UTF-8 encoding, Unicode-encoding, etc.

CAPEC-76: Manipulating Web Input to File System Calls

An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.

CAPEC-78: Using Escaped Slashes in Alternate Encoding

This attack targets the use of the backslash in alternate encoding. An adversary can provide a backslash as a leading character and causes a parser to believe that the next character is special. This is called an escape. By using that trick, the adversary tries to exploit alternate ways to encode the same character which leads to filter problems and opens avenues to attack.

CAPEC-79: Using Slashes in Alternate Encoding

This attack targets the encoding of the Slash characters. An adversary would try to exploit common filtering problems related to the use of the slashes characters to gain access to resources on the target host. Directory-driven systems, such as file systems and databases, typically use the slash character to indicate traversal between directories or other container components. For murky historical reasons, PCs (and, as a result, Microsoft OSs) choose to use a backslash, whereas the UNIX world typically makes use of the forward slash. The schizophrenic result is that many MS-based systems are required to understand both forms of the slash. This gives the adversary many opportunities to discover and abuse a number of common filtering problems. The goal of this pattern is to discover server software that only applies filters to one version, but not the other.