CVSS 4.0
7.0 highCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:NCVE-2026-88008
High (7.0) in traefik traefik. EPSS 0.5% chance of exploitation in the next 30 days. Fixed in github.com/traefik/traefik/v3 3.7.13.
Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend accepts h2c and returns 101 Switching Protocols, Traefik enters a raw tunnel and no longer applies routers, BasicAuth, ForwardAuth, IPAllowList, RateLimit, access logging, metrics, or tracing to later HTTP/2 requests, allowing an unauthenticated request through an unprotected route to reach protected paths on the same backend. This issue is fixed in 2.11.57 and 3.7.13.
Severity
CVSS 3.1
9.1 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N- EPSS
- 0.5% chance of exploitation in the next 30 days; higher than 41% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-444, CWE-863
- Published
- Modified
- Record from
- the NVD, synced
Affected
- traefik:traefik
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-w4v4-9rw7-5326 | Go | github.com/traefik/traefik/v3 | >=3.4.2 <3.7.13 | 3.7.13 |
| GHSA-w4v4-9rw7-5326 | Go | github.com/traefik/traefik/v2 | >=2.11.26 <2.11.57 | 2.11.57 |
| GO-2026-6468 | Go | github.com/traefik/traefik | all versions | no fix published |
| GO-2026-6468 | Go | github.com/traefik/traefik/v2 | >=2.11.26 <2.11.57 | 2.11.57 |
| GO-2026-6468 | Go | github.com/traefik/traefik/v3 | >=3.4.2 <3.7.13 | 3.7.13 |
References
- https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3
- https://github.com/traefik/traefik/pull/13797
- https://github.com/traefik/traefik/releases/tag/v2.11.57
- https://github.com/traefik/traefik/releases/tag/v3.7.13
- https://github.com/traefik/traefik/security/advisories/GHSA-w4v4-9rw7-5326