CVE-2026-88008

Published: Sep 10, 2026Modified: Sep 14, 2026

7.0

Vector

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

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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:XShow less

Source: security-advisories@github.com (Secondary)

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 (2)

Products: Traefik: Traefik

1 product

Configuration A

2 vulnerable

Vulnerable Software	Affected Versions
Traefik Traefik	2.11.26 ≤ version < 2.11.57
Traefik Traefik	3.4.2 ≤ version < 3.7.13

Related CWEs

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.

Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.

References (5)

https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3

Source: security-advisories@github.com

Patch

https://github.com/traefik/traefik/pull/13797

Source: security-advisories@github.com

Issue TrackingPatch

https://github.com/traefik/traefik/releases/tag/v2.11.57

Source: security-advisories@github.com

Release Notes

https://github.com/traefik/traefik/releases/tag/v3.7.13

Source: security-advisories@github.com

Release Notes

https://github.com/traefik/traefik/security/advisories/GHSA-w4v4-9rw7-5326

Source: security-advisories@github.com

PatchVendor Advisory

Timeline

No history available yet.