{"id":"CVE-2026-35051","state":"PUBLISHED","title":"Traefik: ForwardAuth trustForwardHeader=false allows spoofed X-Forwarded-Prefix to bypass auth","description":"Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is an authentication bypass vulnerability in Traefik's ForwardAuth middleware when trustForwardHeader=false is configured and Traefik is deployed behind a trusted upstream proxy. 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Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is an authentication bypass vulnerability in Traefik's ForwardAuth middleware when trustForwardHeader=false is configured and Traefik is deployed behind a trusted upstream proxy. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2."}],"affected":[{"vendor":"traefik","product":"traefik","versions":[{"version":"< 2.11.43","status":"affected"},{"version":">= 3.0.0-beta1, < 3.6.14","status":"affected"},{"version":">= 3.7.0-ea.1, < 3.7.0-rc.2","status":"affected"}]}],"references":[{"url":"https://github.com/traefik/traefik/security/advisories/GHSA-6384-m2mw-rf54","name":"https://github.com/traefik/traefik/security/advisories/GHSA-6384-m2mw-rf54","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/traefik/traefik/releases/tag/v2.11.43","name":"https://github.com/traefik/traefik/releases/tag/v2.11.43","tags":["x_refsource_MISC"]},{"url":"https://github.com/traefik/traefik/releases/tag/v3.6.14","name":"https://github.com/traefik/traefik/releases/tag/v3.6.14","tags":["x_refsource_MISC"]},{"url":"https://github.com/traefik/traefik/releases/tag/v3.7.0-rc.2","name":"https://github.com/traefik/traefik/releases/tag/v3.7.0-rc.2","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"LOW","subAvailabilityImpact":"NONE","baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-345","lang":"en","description":"CWE-345: Insufficient Verification of Data Authenticity","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-04-30T20:26:06.716Z"},"source":{"advisory":"GHSA-6384-m2mw-rf54","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-01T21:19:58.832533Z","id":"CVE-2026-35051","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-01T21:20:11.714Z"}},{"title":"Traefik: github.com/traefik/traefik: Traefik: Authentication bypass in ForwardAuth middleware","descriptions":[{"lang":"en","value":"A flaw was found in Traefik, an HTTP reverse proxy and load balancer. This authentication bypass vulnerability exists in Traefik's ForwardAuth middleware when the `trustForwardHeader` setting is configured as `false` and Traefik is deployed behind a trusted upstream proxy. A remote attacker could exploit this to bypass authentication, potentially gaining unauthorized access to protected resources."}],"affected":[{"vendor":"Red Hat","product":"Red Hat OpenShift Dev Spaces 3.28","packageName":"devspaces/traefik-rhel9","defaultStatus":"affected","versions":[{"version":"1779786779","status":"unaffected","lessThan":"*","versionType":"rpm"}],"collectionURL":"https://catalog.redhat.com/software/containers/","cpes":["cpe:/a:redhat:openshift_devspaces:3.28::el9"]}],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-35051","tags":["vdb-entry","x_refsource_REDHAT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2464235","name":"RHBZ#2464235","tags":["issue-tracking","x_refsource_REDHAT"]},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-35051.json","tags":["x_sadp-csaf-vex"]},{"url":"https://access.redhat.com/errata/RHSA-2026:21772","tags":["vendor-advisory","x_refsource_REDHAT"]}],"metrics":[{"other":{"content":{"namespace":"https://access.redhat.com/security/updates/classification/","value":"Important"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":8.2,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-501","description":"Trust Boundary Violation","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"redhat-SADP","orgId":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","dateUpdated":"2026-07-15T01:03:12.192Z"},"datePublic":"2026-04-30T20:26:06.716Z","solutions":[{"lang":"en","value":"RHSA-2026:21772: Red Hat OpenShift Dev Spaces 3.28"}],"timeline":[{"lang":"en","time":"2026-04-30T21:01:28.437Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-04-30T20:26:06.716Z","value":"Made public."}],"workarounds":[{"lang":"en","value":"To mitigate this issue, ensure that the `trustForwardHeader` setting in Traefik's ForwardAuth middleware is not explicitly configured as `false` unless absolutely necessary. If Traefik is deployed behind a trusted upstream proxy, review the configuration to ensure that `trustForwardHeader` is either set to `true` or omitted, allowing Traefik to correctly process forwarded headers for authentication. If this configuration is modified, a restart or reload of the Traefik service may be required for the changes to take effect."}],"x_adpType":"supplier","x_generator":{"engine":"sadp-cli 1.0.0"}}]}}}