CVEvulnerability

CVE-2026-88008

7.0 HIGH Published 2026-09-10 Modified 2026-09-14 Official page ↗
Status
Analyzed
Published
2026-09-10
Last modified
2026-09-14
Assigner
[email protected]
CVSS 4.0 ([email protected])
7.0 HIGH — CVSS:4.0/AV:N/AC:L/AT:P/PR:N/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
CVSS 3.1 ([email protected])
9.1 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weaknesses
CWE-444, CWE-863

Description

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.

Affected configurations

• traefik traefik (>= 2.11.26 < 2.11.57) • traefik traefik (>= 3.4.2 < 3.7.13)

Related

Weakness · CWE (2)

  • CWE-444 Inconsistent Interpretation of HTTP Requests weakness
  • CWE-863 Incorrect Authorization weakness

References