Vulnerability-Lookup

CVE-2025-66490 (GCVE-0-2025-66490)

Vulnerability from cvelistv5 – Published: 2025-12-09 00:35 – Updated: 2025-12-09 16:03

Title

Traefik doesn't Prevent Path Normalization Bypass in Router + Middleware Rules

Summary

Traefik is an HTTP reverse proxy and load balancer. For versions prior to 2.11.32 and 2.11.31 through 3.6.2, requests using PathPrefix, Path or PathRegex matchers can bypass path normalization. When Traefik uses path-based routing, requests containing URL-encoded restricted characters (/, \, Null, ;, ?, #) can bypass the middleware chain and reach unintended backends. For example, a request to http://mydomain.example.com/admin%2F could reach service-a without triggering my-security-middleware, bypassing security controls for the /admin/ path. This issue is fixed in versions 2.11.32 and 3.6.3.

Severity

6.9 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-12-09 14:17 UTC

CWE

CWE-436 - Interpretation Conflict

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/traefik/traefik/security/advis…	x_refsource_CONFIRM
https://github.com/traefik/traefik/releases/tag/v…	x_refsource_MISC
https://github.com/traefik/traefik/releases/tag/v3.6.4	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
traefik	traefik	Affected: github.com/traefik/traefik/v3 < 3.6.3 Affected: github.com/traefik/traefik/v2 < 2.11.32 Affected: github.com/traefik/traefik <= 1.7.34	guessed

Show details on NVD website

JSON

To clipboard

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}

CERTFR-2025-AVI-1077

Vulnerability from certfr_avis - Published: 2025-12-08 - Updated: 2025-12-08

De multiples vulnérabilités ont été découvertes dans Traefik. Elles permettent à un attaquant de provoquer une élévation de privilèges, une atteinte à la confidentialité des données et un contournement de la politique de sécurité.

Le CERT-FR a connaissance d'une preuve de concept publique pour la vulnérabilité CVE-2025-66490.

Solutions

Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation).

Impacted products

	Vendor	Product	Description
	Traefik	Traefik	Traefik versions 3.5.x et 3.6.x antérieures à v3.6.3
	Traefik	Traefik	Traefik versions antérieures à v2.11.32

References

Title

Publication Time

FKIE_CVE-2025-66490

Vulnerability from fkie_nvd - Published: 2025-12-09 01:16 - Updated: 2026-06-17 09:56

Severity

6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Summary

References

URL	Tags
security-advisories@github.com	https://github.com/traefik/traefik/releases/tag/v2.11.32	Release Notes
security-advisories@github.com	https://github.com/traefik/traefik/releases/tag/v3.6.4	Release Notes
security-advisories@github.com	https://github.com/traefik/traefik/security/advisories/GHSA-gm3x-23wp-hc2c	Exploit, Vendor Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/traefik/traefik/security/advisories/GHSA-gm3x-23wp-hc2c	Exploit, Vendor Advisory

Impacted products

	Vendor	Product	Version
	traefik	traefik	*
	traefik	traefik	*

JSON

To clipboard

{
  "affected": [
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          "vendor": "traefik",
          "versions": [
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              "status": "affected",
              "version": "github.com/traefik/traefik/v3  \u003c 3.6.3"
            },
            {
              "status": "affected",
              "version": "github.com/traefik/traefik/v2 \u003c 2.11.32"
            },
            {
              "status": "affected",
              "version": "github.com/traefik/traefik \u003c= 1.7.34"
            }
          ]
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      ],
      "source": "security-advisories@github.com"
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              "matchCriteriaId": "A212D168-0836-4D72-B2D9-9209C299471D",
              "versionEndExcluding": "2.11.32",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "0ED22672-D0CC-47CC-A70A-E270FDA55FBC",
              "versionEndExcluding": "3.6.3",
              "versionStartIncluding": "3.0.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Traefik is an HTTP reverse proxy and load balancer. For versions prior to 2.11.32 and 2.11.31 through 3.6.2, requests using PathPrefix, Path or PathRegex matchers can bypass path normalization. When Traefik uses path-based routing, requests containing URL-encoded restricted characters (/, \\, Null, ;, ?, #) can bypass the middleware chain and reach unintended backends. For example, a request to http://mydomain.example.com/admin%2F could reach service-a without triggering my-security-middleware, bypassing security controls for the /admin/ path. This issue is fixed in versions 2.11.32 and 3.6.3."
    }
  ],
  "id": "CVE-2025-66490",
  "lastModified": "2026-06-17T09:56:55.580",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 2.5,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.9,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "LOW",
          "subIntegrityImpact": "LOW",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-66490",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2025-12-09T14:17:38.617610Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2025-12-09T01:16:55.540",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/traefik/traefik/releases/tag/v2.11.32"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/traefik/traefik/releases/tag/v3.6.4"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/traefik/traefik/security/advisories/GHSA-gm3x-23wp-hc2c"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/traefik/traefik/security/advisories/GHSA-gm3x-23wp-hc2c"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-436"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

GHSA-GM3X-23WP-HC2C

Vulnerability from github – Published: 2025-12-08 16:42 – Updated: 2025-12-17 00:44

Summary

Path Normalization Bypass in Traefik Router + Middleware Rules

Details

Impact

There is a potential vulnerability in Traefik managing the requests using a PathPrefix, Path or PathRegex matcher.

When Traefik is configured to route the requests to a backend using a matcher based on the path; if the request path contains an encoded restricted character from the following set ('/', '\', 'Null', ';', '?', '#'), it’s possible to target a backend, exposed using another router, by-passing the middlewares chain.

Example

apiVersion: traefik.io/v1alpha1
kind: IngressRoute
metadata:
  name: my-service
spec:
  routes:
    - match: PathPrefix(‘/admin/’)
      kind: Rule
      services:
        - name: service-a
          port: 8080
      middlewares:
        - name: my-security-middleware
    - match: PathPrefix(‘/’)
      kind: Rule
      services:
        - name: service-a
          port: 8080

In such a case, the request http://mydomain.example.com/admin%2F will reach the backend service-a without operating the middleware my-security-middleware and passing the security put in place for the /admin/ path.

Patches

https://github.com/traefik/traefik/releases/tag/v2.11.32
https://github.com/traefik/traefik/releases/tag/v3.6.4

For more information

If you have any questions or comments about this advisory, please open an issue.

Original Description### Summary A vulnerability exists in Traefik’s path matching logic that allows attackers to bypass access-control middleware (e.g., blocking rules) by using URL-encoded paths. I found this vulnerability while playing PwnSec CTF 2025 with my team @0xL4ugh ### Details Traefik evaluates router rules before decoding or normalizing the request path, but forwards the request after decoding to the backend service. As a result, routes meant to block access to sensitive endpoints (such as internal, beta, or admin endpoints) can be trivially bypassed. ### PoC Traefik configuration used in this issue : ```[http.routers.flask-router-report-deny] entryPoints = ["web"] rule = "PathPrefix(`/report_note`)" priority = 10 middlewares = ["block-access"] service = "flask-service" [http.middlewares.block-access.replacePathRegex] regex = ".*" replacement = "/blocked"

The intention is to block all access to /report_note.

However, the following request bypasses the block:

POST /%2freport_note HTTP/1.1 Host: localhost:62814 ``` ### Impact Access Control Bypass: Any endpoint intended to be blocked (e.g., admin/debug/beta APIs) can be accessed by URL-encoding slashes or other characters. This could lead to: - Unauthorized access to restricted endpoints - Execution of protected internal functionality - Potential privilege escalation - Bypass of security policies enforced via Traefik routing rules

Severity

6.9 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/traefik/traefik"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "1.7.34"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/traefik/traefik/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.11.32"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/traefik/traefik/v3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.6.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-66490"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-436"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-12-08T16:42:30Z",
    "nvd_published_at": "2025-12-09T01:16:55Z",
    "severity": "MODERATE"
  },
  "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 request path contains an encoded restricted character from the following set **(\u0027/\u0027, \u0027\\\u0027, \u0027Null\u0027, \u0027;\u0027, \u0027?\u0027, \u0027#\u0027)**, it\u2019s 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(\u2018/admin/\u2019)\n      kind: Rule\n      services:\n        - name: service-a\n          port: 8080\n      middlewares:\n        - name: my-security-middleware\n    - match: PathPrefix(\u2018/\u2019)\n      kind: Rule\n      services:\n        - name: service-a\n          port: 8080\n```\n\nIn such a case, the request `http://mydomain.example.com/admin%2F` will reach the backend `service-a` without operating the middleware `my-security-middleware` and passing the security put in place for the `/admin/` path.\n\n## Patches\n\n- https://github.com/traefik/traefik/releases/tag/v2.11.32\n- https://github.com/traefik/traefik/releases/tag/v3.6.4\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\u003cdetails\u003e\n\u003csummary\u003eOriginal Description\u003c/summary\u003e### Summary\nA vulnerability exists in Traefik\u2019s path matching logic that allows attackers to bypass access-control middleware (e.g., blocking rules) by using URL-encoded paths. I found this vulnerability while playing PwnSec CTF 2025 with my team @0xL4ugh\n\n### Details\nTraefik evaluates router rules before decoding or normalizing the request path, but forwards the request after decoding to the backend service. As a result, routes meant to block access to sensitive endpoints (such as internal, beta, or admin endpoints) can be trivially bypassed.\n\n### PoC\nTraefik configuration used in this issue :\n```[http.routers.flask-router-report-deny]\n  entryPoints = [\"web\"]\n  rule = \"PathPrefix(`/report_note`)\"\n  priority = 10\n  middlewares = [\"block-access\"]\n  service = \"flask-service\"\n\n[http.middlewares.block-access.replacePathRegex]\n  regex = \".*\"\n  replacement = \"/blocked\"\n```\nThe intention is to block all access to /report_note.\n\nHowever, the following request bypasses the block:\n```\nPOST /%2freport_note HTTP/1.1\nHost: localhost:62814\n\n\n```\n### Impact\nAccess Control Bypass:\nAny endpoint intended to be blocked (e.g., admin/debug/beta APIs) can be accessed by URL-encoding slashes or other characters.\n\nThis could lead to:\n\n- Unauthorized access to restricted endpoints\n- Execution of protected internal functionality\n- Potential privilege escalation\n- Bypass of security policies enforced via Traefik routing rules\n\u003c/details\u003e",
  "id": "GHSA-gm3x-23wp-hc2c",
  "modified": "2025-12-17T00:44:50Z",
  "published": "2025-12-08T16:42:30Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/traefik/traefik/security/advisories/GHSA-gm3x-23wp-hc2c"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66490"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/traefik/traefik"
    },
    {
      "type": "WEB",
      "url": "https://github.com/traefik/traefik/releases/tag/v2.11.32"
    },
    {
      "type": "WEB",
      "url": "https://github.com/traefik/traefik/releases/tag/v3.6.4"
    }
  ],
  "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:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Path Normalization Bypass in Traefik Router + Middleware Rules"
}

OPENSUSE-SU-2026:10020-1

Vulnerability from csaf_opensuse - Published: 2026-01-08 00:00 - Updated: 2026-09-17 16:50

Summary

traefik-3.6.6-1.1 on GA media

Severity

Moderate

Scope

2 vulnerabilities in this advisory, including CVE-2025-66490.

CVE-2025-66490

7.4 (High)


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

Recommended: 4 products

Open the full advisory

OPENSUSE-SU-2026:10143-1

Vulnerability from csaf_opensuse - Published: 2026-02-03 00:00 - Updated: 2026-09-17 16:52

Summary

traefik2-2.11.35-1.1 on GA media

Severity

Moderate

Scope

4 vulnerabilities in this advisory, including CVE-2025-66490.

CVE-2025-66490

7.4 (High)


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

Recommended: 4 products

Open the full advisory

RHSA-2026:2456

Vulnerability from csaf_redhat - Published: 2026-02-10 17:06 - Updated: 2026-09-20 12:05

Summary

Red Hat Security Advisory: Red Hat OpenShift Dev Spaces 3.26.0 Release.

Severity

Important

Scope

14 vulnerabilities in this advisory, including CVE-2025-66490.

CVE-2025-66490

A path normalization bypass has been discovered in Traefik. When Traefik is configured to route the requests to a backend using a matcher based on the path; if the request path contains an encoded restricted character from the following set ('/', '', 'Null', ';', '?', '#'), it’s possible to target a backend, exposed using another router, by-passing the middlewares chain.

7.4 (High)


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

Fixed: 4 products Known not affected: 57 products

https://access.redhat.com/errata/RHSA-2026:2456

Open the full advisory

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2025-66490 (GCVE-0-2025-66490)

CERTFR-2025-AVI-1077

Solutions

FKIE_CVE-2025-66490

GHSA-GM3X-23WP-HC2C

Impact

Example

Patches

For more information

OPENSUSE-SU-2026:10020-1

OPENSUSE-SU-2026:10143-1

RHSA-2026:2456

Tags

Sightings

Nomenclature

Related by attack behaviour