CVE-2025-47952: Github.com/traefik/traefik/v3 Path Traversal Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-vrch-868g-9jx5",
  "modified" : "2025-11-27T08:04:33Z",
  "published" : "2025-05-28T14:25:09Z",
  "aliases" : [ "CVE-2025-47952" ],
  "summary" : "Traefik allows path traversal using url encoding",
  "details" : "## Impact\n\nThere is a potential vulnerability in Traefik managing the requests using a `PathPrefix`, `Path` or `PathRegex` matcher.\n\nWhen Traefik is configured to route the requests to a backend using a matcher based on the path, if the URL contains a URL encoded string in its path, it’s possible to target a backend, exposed using another router, by-passing the middlewares chain.\n\n## Example\n\n```yaml\napiVersion: traefik.io/v1alpha1\nkind: IngressRoute\nmetadata:\n  name: my-service\nspec:\n  routes:\n    - match: PathPrefix(‘/service’)\n      kind: Rule\n      services:\n        - name: service-a\n          port: 8080\n      middlewares:\n        - name: my-middleware-a\n    - match: PathPrefix(‘/service/sub-path’)\n      kind: Rule\n      services:\n        - name: service-a\n          port: 8080\n```\n\nIn such a case, the request `http://mydomain.example.com/service/sub-path/%2e%2e/other-path` will reach the backend `my-service-a` without operating the middleware `my-middleware-a` unless the computed path is `http://mydomain.example.com/service/other-path` and should be computes by the first router (operating `my-middleware-a`).\n\n## Patches\n\n- https://github.com/traefik/traefik/releases/tag/v2.11.25\n- https://github.com/traefik/traefik/releases/tag/v3.4.1\n\n## For more information\n\nIf you have any questions or comments about this advisory, please [open an issue](https://github.com/traefik/traefik/issues).\n\n<details>\n<summary>Original Description</summary>\n### Summary\n\nPath traversal with \"/../\" using URL encodings (\"/%2e%2e\") allows for circumventing routing rules. \n\n### Details\n\nWhen having defined a route, you can path traverse using the URL encoded variant of /../ and reach endpoints that are not made publicly available. This issue has been found and fixed earlier with regular /../ and has been fixed in this CVE. This URL encoding trick works around that\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-32431\n\nSimply implementing a check on the URL encoding won't be sufficient as path traversal can take numerous formats. See examples here:\nhttps://book.hacktricks.wiki/en/pentesting-web/file-inclusion/index.html\n\n### PoC\n\nSetup a service with two endpoints: \"/public\" and \"/private\", which returns a 200 OK for both\nSetup a Traefik proxy with a single route which points to the service using path /public\n\nRegular requests to traefik /public will return 200 OK and to /private should return 404 (response by Traefik)\nWhen making a request to /public/%2e%2e/private you should receive a 200 OK.\n\n### Impact\nImpacts all traefik implementations with path prefix routes that expose only part of the downstream api\n\n### Suggestion\nProvide configuration property which disables all path traversals. Steps:\n1. Decode URL\n2. Evaluate and construct relative path (do traversal before route evaluation)\n3. Compare relative/evaluated path to configured routes (PathPrefix/pathRegexp)\n</details>",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/traefik/traefik/v3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.4.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.4.0"
    }
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/traefik/traefik/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.11.25"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/traefik/traefik"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.7.34"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/traefik/traefik/security/advisories/GHSA-vrch-868g-9jx5"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-47952"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/traefik/traefik/commit/08d5dfee0164aa54dd44a467870042e18e8d3f00"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/traefik/traefik"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/traefik/traefik/releases/tag/v2.11.25"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/traefik/traefik/releases/tag/v3.4.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-05-28T14:25:09Z",
    "nvd_published_at" : "2025-05-30T04:15:46Z"
  }
}