{"answers":{"affected":"11 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-2026-40912 in the wild and no public exploit code.","fix":"Upgrade github.com/traefik/traefik/v3 to a fixed version for your release line: 3.6.14 or 3.7.0-rc.2.","what":"CVE-2026-40912 is a high-severity authentication bypass vulnerability in Traefik Traefik, published on 30 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-40912 and fix it if it is affected.\n\nWhat it is: CVE-2026-40912 is a high-severity authentication bypass vulnerability in Traefik Traefik, published on 30 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-40912 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 3.6.14, 3.7.0-rc.2\n- github.com/traefik/traefik/v3 (Go): affected from 3.0.0-beta1; fixed in 3.6.14\n- github.com/traefik/traefik/v3 (Go): affected from 3.0.0-beta1; fixed in 3.6.14\n- github.com/traefik/traefik/v3 (Go): affected from 3.7.0-ea.1; fixed in 3.7.0-rc.2\n- github.com/traefik/traefik/v3 (Go): affected from 3.7.0-ea.1; fixed in 3.7.0-rc.2\n- github.com/traefik/traefik (Go): affected all versions; no fix listed\n- github.com/traefik/traefik (Go): affected all versions up to 1.7.34; no fix listed\n- github.com/traefik/traefik (Go): affected all versions up to 1.7.34; no fix listed\n- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.43\n- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.43\n- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.43\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-2026-40912/ (Markdown: https://insights.sbomify.com/CVE-2026-40912/index.md)","id":"CVE-2026-40912","markdown":"https://insights.sbomify.com/CVE-2026-40912/index.md","name":"CVE-2026-40912","record":{"aliases":["CLEANSTART-2026-FP02256","GHSA-6jwx-7vp4-9847","GO-2026-5180","MINI-298w-j8fg-2vcg","MINI-5rc8-ch82-76wr","MINI-j5xm-6hhx-jr2q"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["security_bypass","data_read"],"network_reachable":"yes","non_default_config":true,"product_category":"Traefik reverse proxy","requires_auth":"none","summary":"An unauthenticated attacker can bypass authentication in Traefik by exploiting a path desync in StripPrefixRegex, allowing access to protected backend content.","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":7.8,"severity":"high","source":"cna","vector":"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"},"cwes":[{"id":"CWE-22","name":"Improper Limitation of a Pathname to a Restricted Directory"},{"id":"CWE-706","name":"Use of Incorrectly-Resolved Name or Reference"}],"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 a high severity authentication bypass vulnerability in Traefik's StripPrefixRegex middleware when used in combination with ForwardAuth, BasicAuth, or DigestAuth. The middleware matches the regex against the decoded URL path but uses the resulting byte length to slice the percent-encoded raw path. When a dot (or multiple dots) appears in the prefix portion of the URL, the raw path after stripping becomes a dot-segment (e.g. /./admin/secret). ForwardAuth receives this dot-segment path in X-Forwarded-Uri, which does not match the protected path patterns and therefore allows the request through. The backend then normalizes the dot-segment to the real path per RFC 3986 and serves the protected content An unauthenticated attacker can exploit this against any backend that performs dot-segment normalization. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.","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: StripPrefixRegex auth bypass via Path/RawPath desync","id":"CVE-2026-40912","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":"traefik:traefik","products":["traefik:traefik"],"type":"auth_bypass","year":"2026"},"n_packages":11,"n_references":4,"next":{"headline":"Apache Artemis has an Incorrect Authorization issue","id":"CVE-2026-40914"},"packages":[{"ecosystem":"Go","fixed":[],"introduced":["0"],"last_affected":[],"package":"github.com/traefik/traefik","purl":"pkg:golang/github.com/traefik/traefik","source":"GO-2026-5180"},{"ecosystem":"Go","fixed":[],"introduced":["0"],"last_affected":["1.7.34"],"package":"github.com/traefik/traefik","purl":null,"source":"GHSA-6jwx-7vp4-9847"},{"ecosystem":"Go","fixed":[],"introduced":["0"],"last_affected":["1.7.34"],"package":"github.com/traefik/traefik","purl":"pkg:golang/github.com/traefik/traefik","source":"GHSA-6jwx-7vp4-9847"},{"ecosystem":"Go","fixed":["2.11.43"],"introduced":["0"],"last_affected":[],"package":"github.com/traefik/traefik/v2","purl":null,"source":"GHSA-6jwx-7vp4-9847"},{"ecosystem":"Go","fixed":["2.11.43"],"introduced":["0"],"last_affected":[],"package":"github.com/traefik/traefik/v2","purl":"pkg:golang/github.com/traefik/traefik/v2","source":"GHSA-6jwx-7vp4-9847"},{"ecosystem":"Go","fixed":["2.11.43"],"introduced":["0"],"last_affected":[],"package":"github.com/traefik/traefik/v2","purl":"pkg:golang/github.com/traefik/traefik/v2","source":"GO-2026-5180"},{"ecosystem":"Go","fixed":["3.6.14","3.7.0-rc.2"],"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-2026-5180"},{"ecosystem":"Go","fixed":["3.6.14"],"introduced":["3.0.0-beta1"],"last_affected":[],"package":"github.com/traefik/traefik/v3","purl":null,"source":"GHSA-6jwx-7vp4-9847"},{"ecosystem":"Go","fixed":["3.6.14"],"introduced":["3.0.0-beta1"],"last_affected":[],"package":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","source":"GHSA-6jwx-7vp4-9847"},{"ecosystem":"Go","fixed":["3.7.0-rc.2"],"introduced":["3.7.0-ea.1"],"last_affected":[],"package":"github.com/traefik/traefik/v3","purl":null,"source":"GHSA-6jwx-7vp4-9847"},{"ecosystem":"Go","fixed":["3.7.0-rc.2"],"introduced":["3.7.0-ea.1"],"last_affected":[],"package":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","source":"GHSA-6jwx-7vp4-9847"}],"prev":{"headline":"WWBN AVideo YPTSocket WebSocket Broadcast Relay Leads to Unauthenticated Cross-User JavaScript Execution via Client-Side eval() Sinks","id":"CVE-2026-40911"},"products":["traefik"],"published":"2026-04-30","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":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-07-15","vendors":["traefik"]},"summary":"An unauthenticated attacker can bypass authentication in Traefik by exploiting a path desync in StripPrefixRegex, allowing access to protected backend content.","url":"https://insights.sbomify.com/CVE-2026-40912/"}