{"answers":{"affected":"9 open source packages ship an affected version, including github.com/traefik/traefik/v3, github.com/traefik/traefik and github.com/traefik/traefik/v2. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-33433 in the wild and no public exploit code.","fix":"Upgrade github.com/traefik/traefik/v3 to a fixed version for your release line: 3.6.12 or 3.7.0-ea.3.","what":"CVE-2026-33433 is a medium-severity authentication bypass vulnerability in Traefik Traefik, published on 27 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-33433 and fix it if it is affected.\n\nWhat it is: CVE-2026-33433 is a medium-severity authentication bypass vulnerability in Traefik Traefik, published on 27 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-33433 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- github.com/traefik/traefik/v3 (Go): affected from 3.0.0-beta1; fixed in 3.6.12, 3.7.0-ea.3\n- github.com/traefik/traefik/v3 (Go): affected from 3.0.0-beta1; fixed in 3.6.12\n- github.com/traefik/traefik/v3 (Go): affected from 3.0.0-beta1; fixed in 3.6.12\n- github.com/traefik/traefik/v3 (Go): affected from 3.7.0-ea.1; fixed in 3.7.0-ea.3\n- github.com/traefik/traefik/v3 (Go): affected from 3.7.0-ea.1; fixed in 3.7.0-ea.3\n- github.com/traefik/traefik (Go): affected all versions; no fix listed\n- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.42\n- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.42\n- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.42\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-33433/ (Markdown: https://insights.sbomify.com/CVE-2026-33433/index.md)","id":"CVE-2026-33433","markdown":"https://insights.sbomify.com/CVE-2026-33433/index.md","name":"CVE-2026-33433","record":{"aliases":["CLEANSTART-2026-SB40990","ECHO-f91f-26ea-bbf3","GHSA-qr99-7898-vr7c","GO-2026-4893","MINI-8xqp-fgcv-vmrf","MINI-hf3c-p65f-r4ch","MINI-q76c-8hh9-6362"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["privilege_escalation","security_bypass"],"network_reachable":"yes","non_default_config":true,"product_category":"HTTP reverse proxy","requires_auth":"high_privilege","summary":"An authenticated attacker can impersonate any identity to the backend by exploiting non-canonical header field configurations in Traefik.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"traefik","vendor":"traefik"}],"cvss":{"score":5.1,"severity":"medium","source":"cna","vector":"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"},"cwes":[{"id":"CWE-290","name":"Authentication Bypass by Spoofing"}],"description":"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 — 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.","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Traefik Vulnerable to BasicAuth/DigestAuth Identity Spoofing via Non-Canonical headerField","id":"CVE-2026-33433","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":"traefik:traefik","products":["traefik:traefik"],"type":"auth_bypass","year":"2026"},"n_packages":9,"n_references":4,"next":{"headline":"Wazuh: Rate Limit Bypass via /events Endpoint","id":"CVE-2026-33434"},"packages":[{"ecosystem":"Go","fixed":[],"introduced":["0"],"last_affected":[],"package":"github.com/traefik/traefik","purl":"pkg:golang/github.com/traefik/traefik","source":"GO-2026-4893"},{"ecosystem":"Go","fixed":["2.11.42"],"introduced":["0"],"last_affected":[],"package":"github.com/traefik/traefik/v2","purl":null,"source":"GHSA-qr99-7898-vr7c"},{"ecosystem":"Go","fixed":["2.11.42"],"introduced":["0"],"last_affected":[],"package":"github.com/traefik/traefik/v2","purl":"pkg:golang/github.com/traefik/traefik/v2","source":"GHSA-qr99-7898-vr7c"},{"ecosystem":"Go","fixed":["2.11.42"],"introduced":["0"],"last_affected":[],"package":"github.com/traefik/traefik/v2","purl":"pkg:golang/github.com/traefik/traefik/v2","source":"GO-2026-4893"},{"ecosystem":"Go","fixed":["3.6.12","3.7.0-ea.3"],"introduced":["3.0.0-beta1","3.7.0-ea.1"],"last_affected":[],"package":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","source":"GO-2026-4893"},{"ecosystem":"Go","fixed":["3.6.12"],"introduced":["3.0.0-beta1"],"last_affected":[],"package":"github.com/traefik/traefik/v3","purl":null,"source":"GHSA-qr99-7898-vr7c"},{"ecosystem":"Go","fixed":["3.6.12"],"introduced":["3.0.0-beta1"],"last_affected":[],"package":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","source":"GHSA-qr99-7898-vr7c"},{"ecosystem":"Go","fixed":["3.7.0-ea.3"],"introduced":["3.7.0-ea.1"],"last_affected":[],"package":"github.com/traefik/traefik/v3","purl":null,"source":"GHSA-qr99-7898-vr7c"},{"ecosystem":"Go","fixed":["3.7.0-ea.3"],"introduced":["3.7.0-ea.1"],"last_affected":[],"package":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","source":"GHSA-qr99-7898-vr7c"}],"prev":{"headline":"Roxy-WI has Pre-Authentication LDAP Injection that Leads to Authentication Bypass","id":"CVE-2026-33432"},"products":["traefik"],"published":"2026-03-27","related":[{"cvss_score":9.8,"headline":"HTTP client can remove the X-Forwarded headers in Traefik","id":"CVE-2024-45410","kev_date_added":null,"published":"2024-09-19"},{"cvss_score":9.3,"headline":"Traefik v3.7.0 Authentication Bypass via from-to-www-redirect","id":"CVE-2026-88877","kev_date_added":null,"published":"2026-09-10"},{"cvss_score":9.3,"headline":"Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth","id":"CVE-2026-85595","kev_date_added":null,"published":"2026-09-04"},{"cvss_score":9.1,"headline":"Traefik HTTP/3 Backend NTLM Connection Reuse","id":"CVE-2026-88007","kev_date_added":null,"published":"2026-09-10"},{"cvss_score":8.8,"headline":"Traefik: Rootless HTTP/1 request-target routes as \"/\" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging","id":"CVE-2026-88009","kev_date_added":null,"published":"2026-09-10"},{"cvss_score":8.8,"headline":"Traefik has a possible vulnerability with the path matchers","id":"CVE-2025-32431","kev_date_added":null,"published":"2025-04-21"},{"cvss_score":8.2,"headline":"Traefik v3.7 Authentication Bypass via TLS Option Conflict","id":"CVE-2026-85596","kev_date_added":null,"published":"2026-09-04"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-07-15","vendors":["traefik"]},"summary":"An authenticated attacker can impersonate any identity to the backend by exploiting non-canonical header field configurations in Traefik.","url":"https://insights.sbomify.com/CVE-2026-33433/"}