CWE-22
Allowed-with-ReviewImproper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
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.
13217 vulnerabilities reference this CWE, most recent first.
GHSA-PRVP-V5VW-H6PH
Vulnerability from github – Published: 2023-08-30 18:30 – Updated: 2023-11-03 03:30In Splunk Enterprise versions lower than 8.2.12, 9.0.6, and 9.1.1, an attacker can exploit an absolute path traversal to execute arbitrary code that is located on a separate disk.
{
"affected": [],
"aliases": [
"CVE-2023-40597"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-08-30T17:15:10Z",
"severity": "HIGH"
},
"details": "In Splunk Enterprise versions lower than 8.2.12, 9.0.6, and 9.1.1, an attacker can exploit an absolute path traversal to execute arbitrary code that is located on a separate disk.",
"id": "GHSA-prvp-v5vw-h6ph",
"modified": "2023-11-03T03:30:23Z",
"published": "2023-08-30T18:30:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-40597"
},
{
"type": "WEB",
"url": "https://advisory.splunk.com/advisories/SVD-2023-0806"
},
{
"type": "WEB",
"url": "https://research.splunk.com/application/356bd3fe-f59b-4f64-baa1-51495411b7ad"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-PRW8-XQMJ-467G
Vulnerability from github – Published: 2025-11-18 18:32 – Updated: 2025-11-18 18:32Local Agent DVR versions thru 6.6.1.0 are vulnerable to directory traversal that allows an unauthenticated local attacker to gain access to sensitive information, cause a server-side forgery request (SSRF), or execute OS commands.
{
"affected": [],
"aliases": [
"CVE-2025-63408"
],
"database_specific": {
"cwe_ids": [
"CWE-22",
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-11-18T16:15:45Z",
"severity": "MODERATE"
},
"details": "Local Agent DVR versions thru 6.6.1.0 are vulnerable to directory traversal that allows an unauthenticated local attacker to gain access to sensitive information, cause a server-side forgery request (SSRF), or execute OS commands.",
"id": "GHSA-prw8-xqmj-467g",
"modified": "2025-11-18T18:32:52Z",
"published": "2025-11-18T18:32:52Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-63408"
},
{
"type": "WEB",
"url": "https://ispysoftware.github.io/Agent_API"
},
{
"type": "WEB",
"url": "https://www.ericholub.com/blog/agent-dvr-rce"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-PRWR-G52W-7GJ9
Vulnerability from github – Published: 2025-02-18 06:35 – Updated: 2026-04-08 18:33The Keap Official Opt-in Forms plugin for WordPress is vulnerable to Local File Inclusion in all versions up to, and including, 2.0.1 via the service parameter. This makes it possible for unauthenticated attackers to include PHP files on the server, allowing the execution of any PHP code in those files. This can be used to bypass access controls, obtain sensitive data, or achieve code execution in cases where PHP files can be uploaded and included. If register_argc_argv is enabled on the server and pearcmd.php is installed, this issue might lead to Remote Code Execution.
{
"affected": [],
"aliases": [
"CVE-2024-13725"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-18T05:15:18Z",
"severity": "CRITICAL"
},
"details": "The Keap Official Opt-in Forms plugin for WordPress is vulnerable to Local File Inclusion in all versions up to, and including, 2.0.1 via the service parameter. This makes it possible for unauthenticated attackers to include PHP files on the server, allowing the execution of any PHP code in those files. This can be used to bypass access controls, obtain sensitive data, or achieve code execution in cases where PHP files can be uploaded and included. If register_argc_argv is enabled on the server and pearcmd.php is installed, this issue might lead to Remote Code Execution.",
"id": "GHSA-prwr-g52w-7gj9",
"modified": "2026-04-08T18:33:48Z",
"published": "2025-02-18T06:35:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-13725"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/infusionsoft-official-opt-in-forms/trunk/infusionsoft.php#L2540"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/changeset/3243545"
},
{
"type": "WEB",
"url": "https://wordpress.org/plugins/infusionsoft-official-opt-in-forms"
},
{
"type": "WEB",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/692a5838-4a32-4444-b1a0-018fa25594a9?source=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-PV2F-867W-W3WM
Vulnerability from github – Published: 2022-07-12 00:00 – Updated: 2022-07-16 00:00The rainsoupah/sleep-learner repository through 2021-02-21 on GitHub allows absolute path traversal because the Flask send_file function is used unsafely.
{
"affected": [],
"aliases": [
"CVE-2022-31553"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-07-11T01:15:00Z",
"severity": "CRITICAL"
},
"details": "The rainsoupah/sleep-learner repository through 2021-02-21 on GitHub allows absolute path traversal because the Flask send_file function is used unsafely.",
"id": "GHSA-pv2f-867w-w3wm",
"modified": "2022-07-16T00:00:28Z",
"published": "2022-07-12T00:00:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-31553"
},
{
"type": "WEB",
"url": "https://github.com/github/securitylab/issues/669#issuecomment-1117265726"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L",
"type": "CVSS_V3"
}
]
}
GHSA-PV32-F2VQ-RG33
Vulnerability from github – Published: 2025-09-09 21:30 – Updated: 2025-09-09 21:30Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in CRESTRON TOUCHSCREENS x70 allows Relative Path Traversal.This issue affects TOUCHSCREENS x70: from 3.000.0110.001 before 3.001.0031.001.
Confirmed Affected Hardware: TSW-760, TSW-1060
Confirmed Affected Firmware: 3.002.1061 - (no fix released, product discontinued)
For x70
The Affected Firmware:- 3.000.0110.001 and versions below
The Fixed Firmware:- 3.001.0031.001
{
"affected": [],
"aliases": [
"CVE-2025-47415"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-09T20:15:40Z",
"severity": "MODERATE"
},
"details": "Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027) vulnerability in CRESTRON TOUCHSCREENS x70 allows Relative Path Traversal.This issue affects TOUCHSCREENS x70: from 3.000.0110.001 before 3.001.0031.001.\n\n\n\n\n\n\n\n\n\n\n\nConfirmed Affected Hardware:\u202fTSW-760, TSW-1060 \n\n\n\nConfirmed Affected Firmware:\u202f3.002.1061\u00a0- (no fix released, product discontinued)\n\n\n\n\u00a0\n\nFor x70\u202f\u00a0\n\n\n\nThe Affected Firmware:- 3.000.0110.001 \u202fand versions below \n\n\n\nThe Fixed Firmware:- 3.001.0031.001",
"id": "GHSA-pv32-f2vq-rg33",
"modified": "2025-09-09T21:30:29Z",
"published": "2025-09-09T21:30:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-47415"
},
{
"type": "WEB",
"url": "https://security.crestron.com"
},
{
"type": "WEB",
"url": "https://www.crestron.com/Software-Firmware/Firmware/Touchpanels/TS-770-TS-1070-TSS-770-TSS-1070-TSW-570/3-002-0040-001"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-PV35-QW98-98C8
Vulnerability from github – Published: 2022-05-24 16:57 – Updated: 2024-04-04 02:05In GoogleContactsSyncAdapter, there is a possible path traversal due to improper input sanitization. This could lead to a bypass of user interaction requirements with no additional execution privileges needed. User interaction is not needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-32748076
{
"affected": [],
"aliases": [
"CVE-2019-9281"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-09-27T19:15:00Z",
"severity": "HIGH"
},
"details": "In GoogleContactsSyncAdapter, there is a possible path traversal due to improper input sanitization. This could lead to a bypass of user interaction requirements with no additional execution privileges needed. User interaction is not needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-32748076",
"id": "GHSA-pv35-qw98-98c8",
"modified": "2024-04-04T02:05:00Z",
"published": "2022-05-24T16:57:19Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-9281"
},
{
"type": "WEB",
"url": "https://source.android.com/security/bulletin/android-10"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-PV37-MF6H-P9J8
Vulnerability from github – Published: 2025-10-09 21:31 – Updated: 2025-10-09 21:31Newforma Info Exchange (NIX) '/UserWeb/Common/UploadBlueimp.ashx' allows an authenticated attacker to upload an arbitrary file to any location writable by the NIX application. An attacker can upload and run a web shell or other content executable by the web server. An attacker can also delete directories. In Newforma before 2023.1, anonymous access is enabled by default (CVE-2025-35062), allowing an otherwise unauthenticated attacker to effectively authenticate as 'anonymous' and exploit this file upload vulnerability.
{
"affected": [],
"aliases": [
"CVE-2025-35055"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-09T21:15:36Z",
"severity": "HIGH"
},
"details": "Newforma Info Exchange (NIX) \u0027/UserWeb/Common/UploadBlueimp.ashx\u0027 allows an authenticated attacker to upload an arbitrary file to any location writable by the NIX application. An attacker can upload and run a web shell or other content executable by the web server. An attacker can also delete directories. In Newforma before 2023.1, anonymous access is enabled by default (CVE-2025-35062), allowing an otherwise unauthenticated attacker to effectively authenticate as \u0027anonymous\u0027 and exploit this file upload vulnerability.",
"id": "GHSA-pv37-mf6h-p9j8",
"modified": "2025-10-09T21:31:12Z",
"published": "2025-10-09T21:31:12Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-35055"
},
{
"type": "WEB",
"url": "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2025/va-25-282-01.json"
},
{
"type": "WEB",
"url": "https://www.cve.org/CVERecord?id=CVE-2025-35055"
},
{
"type": "WEB",
"url": "https://www.cve.org/CVERecord?id=CVE-2025-35062"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-PV3R-P93C-QVJX
Vulnerability from github – Published: 2022-05-24 19:19 – Updated: 2022-05-24 19:19Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in the UpdateServer component of Bitdefender GravityZone allows an attacker to execute arbitrary code on vulnerable instances. This issue affects: Bitdefender GravityZone versions prior to 3.3.8.249.
{
"affected": [],
"aliases": [
"CVE-2021-3823"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-10-28T14:15:00Z",
"severity": "CRITICAL"
},
"details": "Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027) vulnerability in the UpdateServer component of Bitdefender GravityZone allows an attacker to execute arbitrary code on vulnerable instances. This issue affects: Bitdefender GravityZone versions prior to 3.3.8.249.",
"id": "GHSA-pv3r-p93c-qvjx",
"modified": "2022-05-24T19:19:03Z",
"published": "2022-05-24T19:19:03Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-3823"
},
{
"type": "WEB",
"url": "https://www.bitdefender.com/support/security-advisories/path-traversal-vulnerability-in-bitdefender-gravitzone-update-server-in-relay-mode-va-10039"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-PV5W-4P9Q-P3V2
Vulnerability from github – Published: 2026-05-11 19:40 – Updated: 2026-06-08 23:53Summary
Kysely 0.28.12 added a sanitizeStringLiteral() call inside DefaultQueryCompiler.visitJSONPathLeg (commit 0a602bf, PR #1727) to fix CVE-2026-32763 (GHSA-wmrf-hv6w-mr66). The fix only doubles single quotes (' → ''); it does not escape JSON-path metacharacters (., [, ], *, **, ?). When attacker-controlled input flows into eb.ref(col, '->$').key(input) or .at(input) — including type-safe code where the JSON column is shaped like Record<string, T> so K extends string is the inferred type — every dot becomes a path-leg separator, letting an attacker traverse from the intended key into sibling and child fields the developer never meant to expose. The result is read access (and, in update statements, write access) to JSON sub-fields outside the intended scope across MySQL, PostgreSQL ->$/->>$, and SQLite.
- Project: Kysely — TypeScript SQL query builder (npm
kysely); affects MySQL, PostgreSQL->$/->>$, and SQLite dialects. - Source reviewed:
kysely-org/kysely@master(73192e4, version0.28.16). - Deployed artefact validated:
kysely@0.28.16from npm. - Affected file(s):
src/query-compiler/default-query-compiler.ts(lines 1611–1639, 1821–1823)src/query-builder/json-path-builder.ts(lines 93–196)src/dialect/mysql/mysql-query-compiler.ts(overridessanitizeStringLiteralbut inherits the same behaviour for path legs — escapes\and', nothing else)- CWE: CWE-89 — Improper Neutralization of Special Elements used in an SQL Command, with CWE-915 / CWE-1284 (improper validation of specified quantity in input) flavours for the JSON-path sub-language.
- OWASP 2021: A03:2021 — Injection.
Vulnerable code
src/query-compiler/default-query-compiler.ts:1625-1639:
protected override visitJSONPathLeg(node: JSONPathLegNode): void {
const isArrayLocation = node.type === 'ArrayLocation'
this.append(isArrayLocation ? '[' : '.') // (1)
this.append(
typeof node.value === 'string'
? this.sanitizeStringLiteral(node.value) // (2)
: String(node.value),
)
if (isArrayLocation) {
this.append(']')
}
}
src/query-compiler/default-query-compiler.ts:1821-1823:
protected sanitizeStringLiteral(value: string): string {
return value.replace(LIT_WRAP_REGEX, "''") // (3)
}
with LIT_WRAP_REGEX = /'/g.
src/query-builder/json-path-builder.ts:151-167:
key<
K extends any[] extends O
? never
: O extends object
? keyof NonNullable<O> & string
: never,
O2 = undefined extends O
? null | NonNullable<NonNullable<O>[K]>
: null extends O
? null | NonNullable<NonNullable<O>[K]>
: // when the object has non-specific keys, e.g. Record<string, T>, should infer `T | null`!
string extends keyof NonNullable<O>
? null | NonNullable<NonNullable<O>[K]>
: NonNullable<O>[K],
>(key: K): TraversedJSONPathBuilder<S, O2> {
return this.#createBuilderWithPathLeg('Member', key) // (4)
}
src/query-builder/json-path-builder.ts:169-196:
#createBuilderWithPathLeg(
legType: JSONPathLegType,
value: string | number, // (5)
): TraversedJSONPathBuilder<any, any> {
// ...
return new TraversedJSONPathBuilder(
JSONPathNode.cloneWithLeg(
this.#node,
JSONPathLegNode.create(legType, value), // (6)
),
)
}
At (1) the compiler emits the path-leg separator — . for member access or [ for array index. At (2) the user-supplied string is run through sanitizeStringLiteral, which at (3) only doubles single quotes ('). Dots, brackets, asterisks, double-asterisks and question marks — every reserved character of the SQL/JSON path mini-language — pass through unmodified.
At (4) .key(K) types K as keyof NonNullable<O> & string. When the JSON column is typed as Record<string, T> (a common shape for free-form metadata blobs) the inferred K is just string, so attacker-controlled input is type-safe and does not need a Kysely<any> escape hatch — this finding is broader than GHSA-wmrf-hv6w-mr66 (CVE-2026-32763), which only covered the Kysely<any> case. At (5)/(6) the runtime accepts any string | number regardless of legType, so a string sent into .at(...) ('last'/'#-N' per the public type signature) also reaches the same emitter and can carry ] to break out of the bracket.
The fix at 0a602bf only addressed the single-quote → string-literal escape. The JSON-path metacharacter set was overlooked.
MysqlQueryCompiler.sanitizeStringLiteral (src/dialect/mysql/mysql-query-compiler.ts:47-51) overrides the helper to also escape backslashes — but again, it does nothing for . [ ] * ** ?.
Reproduction (validated locally)
Environment: kysely@0.28.16 + better-sqlite3@12.x, Node 22, on macOS. The PoC harness lives in /Users/admin/joplin_research/kysely-poc/.
Step 1 — Compiled-SQL evidence across all three dialects
/Users/admin/joplin_research/kysely-poc/poc.mjs (no DB, just .compile()):
$ node poc.mjs
===== MySQL =====
--- baseline: .key("nick") ---
SQL: select `profile`->'$.nick' as `out` from `person`
--- INJECTION via .key(ATTACKER) -- "nick.secret_field" ---
SQL: select `profile`->'$.nick.secret_field' as `out` from `person`
--- INJECTION via .key("*") -- wildcard reaches all keys ---
SQL: select `profile`->'$.*' as `out` from `person`
--- INJECTION via .at(ATTACKER3) -- bracket escape ---
SQL: select `profile`->'$[].secret]' as `out` from `person`
===== PostgreSQL (->$ uses jsonpath, MySQL-like) =====
--- baseline: .key("nick") ---
SQL: select "profile"->'$.nick' as "out" from "person"
--- INJECTION via .key(ATTACKER) ---
SQL: select "profile"->'$.nick.secret_field' as "out" from "person"
===== SQLite =====
--- baseline: .key("nick") ---
SQL: select "profile"->>'$.nick' as "value" from "person"
--- INJECTION via .key(ATTACKER) ---
SQL: select "profile"->>'$.nick.secret_field' as "out" from "person"
--- INJECTION via .key("*") ---
SQL: select "profile"->>'$.*' as "out" from "person"
The compiled SQL clearly shows the dot inside the user-supplied "key" being interpreted by the database as a path separator: '$.nick' (one leg) becomes '$.nick.secret_field' (two legs). MySQL additionally accepts * as a wildcard reaching every member at the current level.
Step 2 — End-to-end data disclosure on a real database
/Users/admin/joplin_research/kysely-poc/sqlite-runtime.mjs simulates a typical handler that reads one top-level field of the caller's profile:
async function fetchProfileField(userInput) {
return db.selectFrom('me')
.select(eb => eb.ref('profile', '->>$').key(userInput).as('value'))
.where('id', '=', 1)
.execute()
}
The me.profile JSON column for user 1 is:
{
"nick": "alice",
"tagline": "hi",
"internal": {
"ssn": "111-11-1111",
"token": "tok_abcdef",
"admin": true
}
}
The developer's intent: only top-level keys (nick, tagline) are ever requested. internal is private bookkeeping.
$ node sqlite-runtime.mjs
===== Legitimate request =====
userInput = "nick"
compiled SQL: select "profile"->>'$.nick' as "value" from "me" where "id" = ?
result: [ { value: 'alice' } ]
===== Injection: dot lets attacker reach nested "internal" object =====
userInput = "internal.ssn"
compiled SQL: select "profile"->>'$.internal.ssn' as "value" from "me" where "id" = ?
result: [ { value: '111-11-1111' } ]
userInput = "internal.token"
compiled SQL: select "profile"->>'$.internal.token' as "value" from "me" where "id" = ?
result: [ { value: 'tok_abcdef' } ]
userInput = "internal.admin"
compiled SQL: select "profile"->>'$.internal.admin' as "value" from "me" where "id" = ?
result: [ { value: 1 } ]
Expected vs. actual: the application invariant was "the user can only read top-level keys of their profile". The output violates that invariant — internal.ssn, internal.token, and internal.admin are returned even though internal was never meant to be addressable through this endpoint.
The same pattern is exploitable on MySQL (where * and ** wildcards make it strictly worse — a single * enumerates every sibling at the current level in one row) and on PostgreSQL when using the ->$/->>$ operators (which target MySQL-style JSON-path strings on PG ≥ 17 / via jsonb_path_query).
Impact
- Authorization bypass on JSON sub-fields. Any kysely-built query whose JSON-path key/index argument is partially or fully attacker-controlled — even in fully type-safe code where the column type is
Record<string, T>— leaks data the developer believed was scoped behind the explicitly-listed key. SSNs, tokens, admin flags, internal IDs, anything stored as a nested member of the same JSON document is reachable. - Wildcard reads on MySQL / PostgreSQL
->$.key('*')compiles to'$.*', returning the array of every value at the current depth in one round-trip.key('**')recurses across the whole document. The fix does not strip either token. - Write access in update statements. Kysely uses the same path compiler for
update().set(eb => eb.ref(col, '->$').key(input), value)-style writes (andjsonb_sethelpers). An attacker who can drive both the path and the value can therefore write into nested fields they should not be able to set — for example flipping anadminflag or rewriting a nested role. - Bypasses the recently-fixed precedent. The maintainers shipped commit
0a602bf(PR #1727) specifically to harden this surface. That fix removed the'(quote) primitive but left every JSON-path metacharacter alone, so the surface is still open against any caller that thought it was now safe. - Practical bounding. The attacker needs a code path where a request-derived string lands in
.key(...)or.at(...). This is a recognised pattern (filter-by-field, dynamicselectfor admin dashboards, Strapi-style JSON-blob columns); it is not a default kysely behaviour but is plausibly common. The vulnerable path is also exercised any time a developer writesdb as Kysely<any>(covered by the olderGHSA-wmrf-hv6w-mr66advisory) — but unlike that advisory, the bug here triggers in fully-typed code onRecord<string, T>columns.
Suggested fix
Treat path legs as a structured emission, not a string-literal escape. The narrowest safe patch is a dedicated sanitizeJSONPathLeg that only emits a known-good character set per leg type and rejects everything else, since JSON-path quoting differs by dialect (MySQL allows "…"-quoted member names; SQLite is more permissive but still has a grammar; PostgreSQL jsonpath is strict).
// src/query-compiler/default-query-compiler.ts
const JSON_PATH_MEMBER_OK = /^[A-Za-z_$][A-Za-z0-9_$]*$/
protected override visitJSONPathLeg(node: JSONPathLegNode): void {
if (node.type === 'ArrayLocation') {
this.append('[')
if (typeof node.value === 'number') {
this.append(String(node.value | 0)) // int-coerce
} else if (node.value === 'last' || /^#-\d+$/.test(node.value)) {
this.append(node.value) // documented dialect tokens
} else {
throw new Error(`invalid JSON array index: ${node.value}`)
}
this.append(']')
return
}
// Member
this.append('.')
if (typeof node.value !== 'string' || !JSON_PATH_MEMBER_OK.test(node.value)) {
// Per-dialect quoted-member escape would go here; default = reject.
throw new Error(`invalid JSON path member: ${JSON.stringify(node.value)}`)
}
this.append(node.value)
}
For dialect-specific behaviour (MySQL "…"-quoted members, SQLite bracket-quoted), each dialect compiler should override the helper and apply the appropriate quoting + double-the-quote rule, the same way sanitizeIdentifier already does.
Consider also: parameterise JSON paths whenever the dialect supports it (PostgreSQL jsonb_path_query($1, $2), MySQL JSON_EXTRACT(?, ?)), so attacker-controlled keys are bound, not concatenated. Add a regression test to test/node/src/json-traversal.test.ts asserting that eb.ref('c','->$').key('a.b').compile().sql is either rejected, or emits MySQL '$."a.b"' / SQLite '$.["a.b"]' (quoted-member form), and explicitly differs from key('a').key('b').
A backstop hardening: tighten the .at() runtime to accept only number | 'last' | '#-${digits}' (matching the type signature), and tighten .key() to only accept strings that match keyof O at runtime when O is statically known.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "kysely"
},
"ranges": [
{
"events": [
{
"introduced": "0.26.0"
},
{
"fixed": "0.28.17"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-44635"
],
"database_specific": {
"cwe_ids": [
"CWE-1284",
"CWE-22",
"CWE-89",
"CWE-915"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-11T19:40:15Z",
"nvd_published_at": "2026-05-27T19:16:20Z",
"severity": "HIGH"
},
"details": "## Summary\n\nKysely 0.28.12 added a `sanitizeStringLiteral()` call inside `DefaultQueryCompiler.visitJSONPathLeg` (commit `0a602bf`, PR #1727) to fix CVE-2026-32763 (`GHSA-wmrf-hv6w-mr66`). The fix only doubles single quotes (`\u0027` \u2192 `\u0027\u0027`); it does **not** escape JSON-path metacharacters (`.`, `[`, `]`, `*`, `**`, `?`). When attacker-controlled input flows into `eb.ref(col, \u0027-\u003e$\u0027).key(input)` or `.at(input)` \u2014 including type-safe code where the JSON column is shaped like `Record\u003cstring, T\u003e` so `K extends string` is the inferred type \u2014 every dot becomes a path-leg separator, letting an attacker traverse from the intended key into sibling and child fields the developer never meant to expose. The result is read access (and, in update statements, write access) to JSON sub-fields outside the intended scope across MySQL, PostgreSQL `-\u003e$`/`-\u003e\u003e$`, and SQLite.\n\n* Project: Kysely \u2014 TypeScript SQL query builder (npm `kysely`); affects MySQL, PostgreSQL `-\u003e$`/`-\u003e\u003e$`, and SQLite dialects.\n* Source reviewed: `kysely-org/kysely` @ `master` (`73192e4`, version `0.28.16`).\n* Deployed artefact validated: `kysely@0.28.16` from npm.\n* Affected file(s):\n * `src/query-compiler/default-query-compiler.ts` (lines 1611\u20131639, 1821\u20131823)\n * `src/query-builder/json-path-builder.ts` (lines 93\u2013196)\n * `src/dialect/mysql/mysql-query-compiler.ts` (overrides `sanitizeStringLiteral` but inherits the same behaviour for path legs \u2014 escapes `\\` and `\u0027`, nothing else)\n* CWE: CWE-89 \u2014 Improper Neutralization of Special Elements used in an SQL Command, with CWE-915 / CWE-1284 (improper validation of specified quantity in input) flavours for the JSON-path sub-language.\n* OWASP 2021: A03:2021 \u2014 Injection.\n\n## Vulnerable code\n\n`src/query-compiler/default-query-compiler.ts:1625-1639`:\n\n```ts\nprotected override visitJSONPathLeg(node: JSONPathLegNode): void {\n const isArrayLocation = node.type === \u0027ArrayLocation\u0027\n\n this.append(isArrayLocation ? \u0027[\u0027 : \u0027.\u0027) // (1)\n\n this.append(\n typeof node.value === \u0027string\u0027\n ? this.sanitizeStringLiteral(node.value) // (2)\n : String(node.value),\n )\n\n if (isArrayLocation) {\n this.append(\u0027]\u0027)\n }\n}\n```\n\n`src/query-compiler/default-query-compiler.ts:1821-1823`:\n\n```ts\nprotected sanitizeStringLiteral(value: string): string {\n return value.replace(LIT_WRAP_REGEX, \"\u0027\u0027\") // (3)\n}\n```\n\nwith `LIT_WRAP_REGEX = /\u0027/g`.\n\n`src/query-builder/json-path-builder.ts:151-167`:\n\n```ts\nkey\u003c\n K extends any[] extends O\n ? never\n : O extends object\n ? keyof NonNullable\u003cO\u003e \u0026 string\n : never,\n O2 = undefined extends O\n ? null | NonNullable\u003cNonNullable\u003cO\u003e[K]\u003e\n : null extends O\n ? null | NonNullable\u003cNonNullable\u003cO\u003e[K]\u003e\n : // when the object has non-specific keys, e.g. Record\u003cstring, T\u003e, should infer `T | null`!\n string extends keyof NonNullable\u003cO\u003e\n ? null | NonNullable\u003cNonNullable\u003cO\u003e[K]\u003e\n : NonNullable\u003cO\u003e[K],\n\u003e(key: K): TraversedJSONPathBuilder\u003cS, O2\u003e {\n return this.#createBuilderWithPathLeg(\u0027Member\u0027, key) // (4)\n}\n```\n\n`src/query-builder/json-path-builder.ts:169-196`:\n\n```ts\n#createBuilderWithPathLeg(\n legType: JSONPathLegType,\n value: string | number, // (5)\n): TraversedJSONPathBuilder\u003cany, any\u003e {\n // ...\n return new TraversedJSONPathBuilder(\n JSONPathNode.cloneWithLeg(\n this.#node,\n JSONPathLegNode.create(legType, value), // (6)\n ),\n )\n}\n```\n\nAt (1) the compiler emits the path-leg separator \u2014 `.` for member access or `[` for array index. At (2) the user-supplied string is run through `sanitizeStringLiteral`, which at (3) only doubles single quotes (`\u0027`). Dots, brackets, asterisks, double-asterisks and question marks \u2014 every reserved character of the SQL/JSON path mini-language \u2014 pass through unmodified.\n\nAt (4) `.key(K)` types `K` as `keyof NonNullable\u003cO\u003e \u0026 string`. When the JSON column is typed as `Record\u003cstring, T\u003e` (a common shape for free-form metadata blobs) the inferred `K` is just `string`, so attacker-controlled input is **type-safe** and does not need a `Kysely\u003cany\u003e` escape hatch \u2014 this finding is *broader* than `GHSA-wmrf-hv6w-mr66` (CVE-2026-32763), which only covered the `Kysely\u003cany\u003e` case. At (5)/(6) the runtime accepts any `string | number` regardless of `legType`, so a string sent into `.at(...)` (`\u0027last\u0027`/`\u0027#-N\u0027` per the public type signature) also reaches the same emitter and can carry `]` to break out of the bracket.\n\nThe fix at `0a602bf` only addressed the single-quote \u2192 string-literal escape. The JSON-path metacharacter set was overlooked.\n\n`MysqlQueryCompiler.sanitizeStringLiteral` (`src/dialect/mysql/mysql-query-compiler.ts:47-51`) overrides the helper to also escape backslashes \u2014 but again, it does nothing for `. [ ] * ** ?`.\n\n## Reproduction (validated locally)\n\nEnvironment: `kysely@0.28.16` + `better-sqlite3@12.x`, Node 22, on macOS. The PoC harness lives in `/Users/admin/joplin_research/kysely-poc/`.\n\n### Step 1 \u2014 Compiled-SQL evidence across all three dialects\n\n`/Users/admin/joplin_research/kysely-poc/poc.mjs` (no DB, just `.compile()`):\n\n```bash\n$ node poc.mjs\n===== MySQL =====\n\n--- baseline: .key(\"nick\") ---\nSQL: select `profile`-\u003e\u0027$.nick\u0027 as `out` from `person`\n\n--- INJECTION via .key(ATTACKER) -- \"nick.secret_field\" ---\nSQL: select `profile`-\u003e\u0027$.nick.secret_field\u0027 as `out` from `person`\n\n--- INJECTION via .key(\"*\") -- wildcard reaches all keys ---\nSQL: select `profile`-\u003e\u0027$.*\u0027 as `out` from `person`\n\n--- INJECTION via .at(ATTACKER3) -- bracket escape ---\nSQL: select `profile`-\u003e\u0027$[].secret]\u0027 as `out` from `person`\n\n===== PostgreSQL (-\u003e$ uses jsonpath, MySQL-like) =====\n\n--- baseline: .key(\"nick\") ---\nSQL: select \"profile\"-\u003e\u0027$.nick\u0027 as \"out\" from \"person\"\n\n--- INJECTION via .key(ATTACKER) ---\nSQL: select \"profile\"-\u003e\u0027$.nick.secret_field\u0027 as \"out\" from \"person\"\n\n===== SQLite =====\n\n--- baseline: .key(\"nick\") ---\nSQL: select \"profile\"-\u003e\u003e\u0027$.nick\u0027 as \"value\" from \"person\"\n\n--- INJECTION via .key(ATTACKER) ---\nSQL: select \"profile\"-\u003e\u003e\u0027$.nick.secret_field\u0027 as \"out\" from \"person\"\n\n--- INJECTION via .key(\"*\") ---\nSQL: select \"profile\"-\u003e\u003e\u0027$.*\u0027 as \"out\" from \"person\"\n```\n\nThe compiled SQL clearly shows the dot inside the user-supplied \"key\" being interpreted by the database as a path separator: `\u0027$.nick\u0027` (one leg) becomes `\u0027$.nick.secret_field\u0027` (two legs). MySQL additionally accepts `*` as a wildcard reaching every member at the current level.\n\n### Step 2 \u2014 End-to-end data disclosure on a real database\n\n`/Users/admin/joplin_research/kysely-poc/sqlite-runtime.mjs` simulates a typical handler that reads one top-level field of the caller\u0027s profile:\n\n```js\nasync function fetchProfileField(userInput) {\n return db.selectFrom(\u0027me\u0027)\n .select(eb =\u003e eb.ref(\u0027profile\u0027, \u0027-\u003e\u003e$\u0027).key(userInput).as(\u0027value\u0027))\n .where(\u0027id\u0027, \u0027=\u0027, 1)\n .execute()\n}\n```\n\nThe `me.profile` JSON column for user 1 is:\n\n```json\n{\n \"nick\": \"alice\",\n \"tagline\": \"hi\",\n \"internal\": {\n \"ssn\": \"111-11-1111\",\n \"token\": \"tok_abcdef\",\n \"admin\": true\n }\n}\n```\n\nThe developer\u0027s intent: only top-level keys (`nick`, `tagline`) are ever requested. `internal` is private bookkeeping.\n\n```bash\n$ node sqlite-runtime.mjs\n===== Legitimate request =====\nuserInput = \"nick\"\n compiled SQL: select \"profile\"-\u003e\u003e\u0027$.nick\u0027 as \"value\" from \"me\" where \"id\" = ?\n result: [ { value: \u0027alice\u0027 } ]\n\n===== Injection: dot lets attacker reach nested \"internal\" object =====\nuserInput = \"internal.ssn\"\n compiled SQL: select \"profile\"-\u003e\u003e\u0027$.internal.ssn\u0027 as \"value\" from \"me\" where \"id\" = ?\n result: [ { value: \u0027111-11-1111\u0027 } ]\n\nuserInput = \"internal.token\"\n compiled SQL: select \"profile\"-\u003e\u003e\u0027$.internal.token\u0027 as \"value\" from \"me\" where \"id\" = ?\n result: [ { value: \u0027tok_abcdef\u0027 } ]\n\nuserInput = \"internal.admin\"\n compiled SQL: select \"profile\"-\u003e\u003e\u0027$.internal.admin\u0027 as \"value\" from \"me\" where \"id\" = ?\n result: [ { value: 1 } ]\n```\n\nExpected vs. actual: the application invariant was \"the user can only read top-level keys of their profile\". The output violates that invariant \u2014 `internal.ssn`, `internal.token`, and `internal.admin` are returned even though `internal` was never meant to be addressable through this endpoint.\n\nThe same pattern is exploitable on MySQL (where `*` and `**` wildcards make it strictly worse \u2014 a single `*` enumerates every sibling at the current level in one row) and on PostgreSQL when using the `-\u003e$`/`-\u003e\u003e$` operators (which target MySQL-style JSON-path strings on PG \u2265 17 / via `jsonb_path_query`).\n\n## Impact\n\n* **Authorization bypass on JSON sub-fields.** Any kysely-built query whose JSON-path key/index argument is partially or fully attacker-controlled \u2014 even in fully type-safe code where the column type is `Record\u003cstring, T\u003e` \u2014 leaks data the developer believed was scoped behind the explicitly-listed key. SSNs, tokens, admin flags, internal IDs, anything stored as a nested member of the same JSON document is reachable.\n* **Wildcard reads on MySQL / PostgreSQL `-\u003e$`.** `key(\u0027*\u0027)` compiles to `\u0027$.*\u0027`, returning the array of every value at the current depth in one round-trip. `key(\u0027**\u0027)` recurses across the whole document. The fix does not strip either token.\n* **Write access in update statements.** Kysely uses the same path compiler for `update().set(eb =\u003e eb.ref(col, \u0027-\u003e$\u0027).key(input), value)`-style writes (and `jsonb_set` helpers). An attacker who can drive both the path and the value can therefore write into nested fields they should not be able to set \u2014 for example flipping an `admin` flag or rewriting a nested role.\n* **Bypasses the recently-fixed precedent.** The maintainers shipped commit `0a602bf` (PR #1727) specifically to harden this surface. That fix removed the `\u0027` (quote) primitive but left every JSON-path metacharacter alone, so the surface is still open against any caller that *thought* it was now safe.\n* **Practical bounding.** The attacker needs a code path where a request-derived string lands in `.key(...)` or `.at(...)`. This is a recognised pattern (filter-by-field, dynamic `select` for admin dashboards, Strapi-style JSON-blob columns); it is not a default kysely behaviour but is plausibly common. The vulnerable path is also exercised any time a developer writes `db as Kysely\u003cany\u003e` (covered by the older `GHSA-wmrf-hv6w-mr66` advisory) \u2014 but unlike that advisory, the bug here triggers in fully-typed code on `Record\u003cstring, T\u003e` columns.\n\n## Suggested fix\n\nTreat path legs as a structured emission, not a string-literal escape. The narrowest safe patch is a dedicated `sanitizeJSONPathLeg` that only emits a known-good character set per leg type and rejects everything else, since JSON-path quoting differs by dialect (MySQL allows `\"\u2026\"`-quoted member names; SQLite is more permissive but still has a grammar; PostgreSQL `jsonpath` is strict).\n\n```ts\n// src/query-compiler/default-query-compiler.ts\nconst JSON_PATH_MEMBER_OK = /^[A-Za-z_$][A-Za-z0-9_$]*$/\n\nprotected override visitJSONPathLeg(node: JSONPathLegNode): void {\n if (node.type === \u0027ArrayLocation\u0027) {\n this.append(\u0027[\u0027)\n if (typeof node.value === \u0027number\u0027) {\n this.append(String(node.value | 0)) // int-coerce\n } else if (node.value === \u0027last\u0027 || /^#-\\d+$/.test(node.value)) {\n this.append(node.value) // documented dialect tokens\n } else {\n throw new Error(`invalid JSON array index: ${node.value}`)\n }\n this.append(\u0027]\u0027)\n return\n }\n // Member\n this.append(\u0027.\u0027)\n if (typeof node.value !== \u0027string\u0027 || !JSON_PATH_MEMBER_OK.test(node.value)) {\n // Per-dialect quoted-member escape would go here; default = reject.\n throw new Error(`invalid JSON path member: ${JSON.stringify(node.value)}`)\n }\n this.append(node.value)\n}\n```\n\nFor dialect-specific behaviour (MySQL `\"\u2026\"`-quoted members, SQLite bracket-quoted), each dialect compiler should override the helper and apply the appropriate quoting + double-the-quote rule, the same way `sanitizeIdentifier` already does.\n\nConsider also: parameterise JSON paths whenever the dialect supports it (PostgreSQL `jsonb_path_query($1, $2)`, MySQL `JSON_EXTRACT(?, ?)`), so attacker-controlled keys are bound, not concatenated. Add a regression test to `test/node/src/json-traversal.test.ts` asserting that `eb.ref(\u0027c\u0027,\u0027-\u003e$\u0027).key(\u0027a.b\u0027).compile().sql` is **either** rejected, **or** emits MySQL `\u0027$.\"a.b\"\u0027` / SQLite `\u0027$.[\"a.b\"]\u0027` (quoted-member form), and explicitly differs from `key(\u0027a\u0027).key(\u0027b\u0027)`.\n\nA backstop hardening: tighten the `.at()` runtime to accept only `number | \u0027last\u0027 | \u0027#-${digits}\u0027` (matching the type signature), and tighten `.key()` to only accept strings that match `keyof O` at runtime when `O` is statically known.",
"id": "GHSA-pv5w-4p9q-p3v2",
"modified": "2026-06-08T23:53:29Z",
"published": "2026-05-11T19:40:15Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/kysely-org/kysely/security/advisories/GHSA-pv5w-4p9q-p3v2"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44635"
},
{
"type": "PACKAGE",
"url": "https://github.com/kysely-org/kysely"
},
{
"type": "WEB",
"url": "https://github.com/kysely-org/kysely/releases/tag/v0.28.17"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Kysely: JSON-path traversal injection via unsanitized path-leg metacharacters in `JSONPathBuilder.key()` / `.at()`"
}
GHSA-PV77-WRQ6-GQ73
Vulnerability from github – Published: 2026-06-22 21:31 – Updated: 2026-06-22 21:31WebP Server Go through 0.14.4 contains a path traversal vulnerability on Windows that allows unauthenticated attackers to read files outside the configured IMG_PATH directory by sending requests with percent-encoded backslashes (%5C) that bypass the path.Clean() sanitization in handler/router.go. Attackers can exploit the discrepancy between Go's forward-slash-only path normalization and Windows file system APIs that treat backslashes and forward slashes as equivalent to access arbitrary files on the host filesystem accessible to the server process.
{
"affected": [],
"aliases": [
"CVE-2026-53779"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-22T19:17:13Z",
"severity": "HIGH"
},
"details": "WebP Server Go through 0.14.4 contains a path traversal vulnerability on Windows that allows unauthenticated attackers to read files outside the configured IMG_PATH directory by sending requests with percent-encoded backslashes (%5C) that bypass the path.Clean() sanitization in handler/router.go. Attackers can exploit the discrepancy between Go\u0027s forward-slash-only path normalization and Windows file system APIs that treat backslashes and forward slashes as equivalent to access arbitrary files on the host filesystem accessible to the server process.",
"id": "GHSA-pv77-wrq6-gq73",
"modified": "2026-06-22T21:31:00Z",
"published": "2026-06-22T21:31:00Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53779"
},
{
"type": "WEB",
"url": "https://github.com/webp-sh/webp_server_go/pull/451"
},
{
"type": "WEB",
"url": "https://github.com/webp-sh/webp_server_go/commit/eb3b5f9289b331cb639cd610b0d1c532d2cc24e0"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/webp-server-go-path-traversal-via-backslash-encoding-on-windows"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
Mitigation MIT-5.1
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
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
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
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
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
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
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
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
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
- 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
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.