{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-33433", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-03-19T18:45:22.436Z", "datePublished": "2026-03-27T13:49:08.455Z", "dateUpdated": "2026-03-27T13:49:08.455Z"}, "containers": {"cna": {"title": "Traefik Vulnerable to BasicAuth/DigestAuth Identity Spoofing via Non-Canonical headerField", "problemTypes": [{"descriptions": [{"cweId": "CWE-290", "lang": "en", "description": "CWE-290: Authentication Bypass by Spoofing", "type": "CWE"}]}], "metrics": [{"cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "HIGH", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "NONE", "baseScore": 5.1, "baseSeverity": "MEDIUM", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N", "version": "4.0"}}], "references": [{"name": "https://github.com/traefik/traefik/security/advisories/GHSA-qr99-7898-vr7c", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/traefik/traefik/security/advisories/GHSA-qr99-7898-vr7c"}, {"name": "https://github.com/traefik/traefik/releases/tag/v2.11.42", "tags": ["x_refsource_MISC"], "url": "https://github.com/traefik/traefik/releases/tag/v2.11.42"}, {"name": "https://github.com/traefik/traefik/releases/tag/v3.6.11", "tags": ["x_refsource_MISC"], "url": "https://github.com/traefik/traefik/releases/tag/v3.6.11"}, {"name": "https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.3", "tags": ["x_refsource_MISC"], "url": "https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.3"}], "affected": [{"vendor": "traefik", "product": "traefik", "versions": [{"version": "< 2.11.42", "status": "affected"}, {"version": ">= 3.0.0-beta1, < 3.6.11", "status": "affected"}, {"version": ">= 3.7.0-ea.1, < 3.7.0-ea.3", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-03-27T13:49:08.455Z"}, "descriptions": [{"lang": "en", "value": "Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.42, 3.6.11, and 3.7.0-ea.3, when `headerField` is configured with a non-canonical HTTP header name (e.g., `x-auth-user` instead of `X-Auth-User`), an authenticated attacker can inject their own canonical version of that header to impersonate any identity to the backend. The backend receives two header entries \u2014 the attacker-injected canonical one is read first, overriding Traefik's non-canonical write. Versions 2.11.42, 3.6.11, and 3.7.0-ea.3 patch the issue."}], "source": {"advisory": "GHSA-qr99-7898-vr7c", "discovery": "UNKNOWN"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.42, 3.6.11, and 3.7.0-ea.3, when `headerField` is configured with a non-canonical HTTP header name (e.g., `x-auth-user` instead of `X-Auth-User`), an authenticated attacker can inject their own canonical version of that header to impersonate any identity to the backend. The backend receives two header entries \u2014 the attacker-injected canonical one is read first, overriding Traefik's non-canonical write. Versions 2.11.42, 3.6.11, and 3.7.0-ea.3 patch the issue."}], "id": "CVE-2026-33433", "lastModified": "2026-03-27T15:16:54.980", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 5.1, "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": "HIGH", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/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"}]}, "published": "2026-03-27T15:16:54.980", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/traefik/traefik/releases/tag/v2.11.42"}, {"source": "security-advisories@github.com", "url": "https://github.com/traefik/traefik/releases/tag/v3.6.11"}, {"source": "security-advisories@github.com", "url": "https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.3"}, {"source": "security-advisories@github.com", "url": "https://github.com/traefik/traefik/security/advisories/GHSA-qr99-7898-vr7c"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-290"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}