Vulnerability-Lookup

CVE-2026-34785 (GCVE-0-2026-34785)

Vulnerability from cvelistv5 – Published: 2026-04-02 16:44 – Updated: 2026-04-02 18:59

Title

Rack: Local file inclusion in `Rack::Static` via URL Prefix Matching

Summary

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

Severity ?

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CWE

CWE-187 - Partial String Comparison
CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor

Assigner

GitHub_M

References

URL

Tags

https://github.com/rack/rack/security/advisories/…

x_refsource_CONFIRM

Impacted products

	Vendor	Product	Version
	rack	rack	Affected: < 2.2.23 Affected: >= 3.0.0.beta1, < 3.1.21 Affected: >= 3.2.0, < 3.2.6

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-34785",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-02T18:58:57.726888Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-02T18:59:08.828Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "rack",
          "vendor": "rack",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.2.23"
            },
            {
              "status": "affected",
              "version": "\u003e= 3.0.0.beta1, \u003c 3.1.21"
            },
            {
              "status": "affected",
              "version": "\u003e= 3.2.0, \u003c 3.2.6"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as \"/css\", it matches any request path that begins with that string, including unrelated paths such as \"/css-config.env\" or \"/css-backup.sql\". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-187",
              "description": "CWE-187: Partial String Comparison",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-200",
              "description": "CWE-200: Exposure of Sensitive Information to an Unauthorized Actor",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-02T16:44:17.134Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq"
        }
      ],
      "source": {
        "advisory": "GHSA-h2jq-g4cq-5ppq",
        "discovery": "UNKNOWN"
      },
      "title": "Rack: Local file inclusion in `Rack::Static` via URL Prefix Matching"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-34785",
    "datePublished": "2026-04-02T16:44:17.134Z",
    "dateReserved": "2026-03-30T19:54:55.556Z",
    "dateUpdated": "2026-04-02T18:59:08.828Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-34785\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-04-02T17:16:24.873\",\"lastModified\":\"2026-04-03T16:10:23.730\",\"vulnStatus\":\"Undergoing Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as \\\"/css\\\", it matches any request path that begins with that string, including unrelated paths such as \\\"/css-config.env\\\" or \\\"/css-backup.sql\\\". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-187\"},{\"lang\":\"en\",\"value\":\"CWE-200\"}]}],\"references\":[{\"url\":\"https://github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq\",\"source\":\"security-advisories@github.com\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-34785\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-04-02T18:58:57.726888Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-04-02T18:59:03.674Z\"}}], \"cna\": {\"title\": \"Rack: Local file inclusion in `Rack::Static` via URL Prefix Matching\", \"source\": {\"advisory\": \"GHSA-h2jq-g4cq-5ppq\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}], \"affected\": [{\"vendor\": \"rack\", \"product\": \"rack\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 2.2.23\"}, {\"status\": \"affected\", \"version\": \"\u003e= 3.0.0.beta1, \u003c 3.1.21\"}, {\"status\": \"affected\", \"version\": \"\u003e= 3.2.0, \u003c 3.2.6\"}]}], \"references\": [{\"url\": \"https://github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq\", \"name\": \"https://github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq\", \"tags\": [\"x_refsource_CONFIRM\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as \\\"/css\\\", it matches any request path that begins with that string, including unrelated paths such as \\\"/css-config.env\\\" or \\\"/css-backup.sql\\\". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-187\", \"description\": \"CWE-187: Partial String Comparison\"}]}, {\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-200\", \"description\": \"CWE-200: Exposure of Sensitive Information to an Unauthorized Actor\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-04-02T16:44:17.134Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-34785\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-02T18:59:08.828Z\", \"dateReserved\": \"2026-03-30T19:54:55.556Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-04-02T16:44:17.134Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

GHSA-H2JQ-G4CQ-5PPQ

Vulnerability from github – Published: 2026-04-02 18:44 – Updated: 2026-04-02 18:44

Summary

Rack::Static prefix matching can expose unintended files under the static root

Details

Summary

Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql".

As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure.

Details

Rack::Static#route_file performs static-route matching using logic equivalent to:

@urls.any? { |url| path.index(url) == 0 }

This checks only whether the request path starts with the configured prefix string. It does not require a path segment boundary after the prefix.

For example, with:

use Rack::Static, urls: ["/css", "/js"], root: "public"

the following path is matched as intended:

/css/style.css

but these paths are also matched:

/css-config.env
/css-backup.sql
/csssecrets.yml

If such files exist under the configured static root, Rack forwards the request to the file server and serves them as static content.

This means a configuration intended to expose only directory trees such as /css/... and /js/... may also expose sibling files whose names begin with those same strings.

Impact

An attacker can request files under the configured static root whose names share a configured URL prefix and obtain their contents.

In affected deployments, this may expose configuration files, secrets, backups, environment files, or other unintended static content located under the same root directory.

Mitigation

Update to a patched version of Rack that enforces a path boundary when matching configured static URL prefixes.
Match only paths that are either exactly equal to the configured prefix or begin with prefix + "/".
Avoid placing sensitive files under the Rack::Static root directory.
Prefer static URL mappings that cannot overlap with sensitive filenames.

Severity ?

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "rack"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.2.23"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "rack"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0.beta1"
            },
            {
              "fixed": "3.1.21"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "rack"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.2.0"
            },
            {
              "fixed": "3.2.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34785"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-187",
      "CWE-200"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-02T18:44:25Z",
    "nvd_published_at": "2026-04-02T17:16:24Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\n`Rack::Static` determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as `\"/css\"`, it matches any request path that begins with that string, including unrelated paths such as `\"/css-config.env\"` or `\"/css-backup.sql\"`.\n\nAs a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure.\n\n## Details\n\n`Rack::Static#route_file` performs static-route matching using logic equivalent to:\n\n```ruby\n@urls.any? { |url| path.index(url) == 0 }\n```\n\nThis checks only whether the request path starts with the configured prefix string. It does not require a path segment boundary after the prefix.\n\nFor example, with:\n\n```ruby\nuse Rack::Static, urls: [\"/css\", \"/js\"], root: \"public\"\n```\n\nthe following path is matched as intended:\n\n```text\n/css/style.css\n```\n\nbut these paths are also matched:\n\n```text\n/css-config.env\n/css-backup.sql\n/csssecrets.yml\n```\n\nIf such files exist under the configured static root, Rack forwards the request to the file server and serves them as static content.\n\nThis means a configuration intended to expose only directory trees such as `/css/...` and `/js/...` may also expose sibling files whose names begin with those same strings.\n\n## Impact\n\nAn attacker can request files under the configured static root whose names share a configured URL prefix and obtain their contents.\n\nIn affected deployments, this may expose configuration files, secrets, backups, environment files, or other unintended static content located under the same root directory.\n\n## Mitigation\n\n* Update to a patched version of Rack that enforces a path boundary when matching configured static URL prefixes.\n* Match only paths that are either exactly equal to the configured prefix or begin with `prefix + \"/\"`.\n* Avoid placing sensitive files under the `Rack::Static` root directory.\n* Prefer static URL mappings that cannot overlap with sensitive filenames.",
  "id": "GHSA-h2jq-g4cq-5ppq",
  "modified": "2026-04-02T18:44:25Z",
  "published": "2026-04-02T18:44:25Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34785"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/rack/rack"
    }
  ],
  "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": "Rack::Static prefix matching can expose unintended files under the static root"
}

FKIE_CVE-2026-34785

Vulnerability from fkie_nvd - Published: 2026-04-02 17:16 - Updated: 2026-04-03 16:10

Severity ?

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as \"/css\", it matches any request path that begins with that string, including unrelated paths such as \"/css-config.env\" or \"/css-backup.sql\". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6."
    }
  ],
  "id": "CVE-2026-34785",
  "lastModified": "2026-04-03T16:10:23.730",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-04-02T17:16:24.873",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-187"
        },
        {
          "lang": "en",
          "value": "CWE-200"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-34785 (GCVE-0-2026-34785)

GHSA-H2JQ-G4CQ-5PPQ

Summary

Details

Impact

Mitigation

FKIE_CVE-2026-34785

Tags

Sightings

Nomenclature