Not a U.S. government website. NDD is an independent vulnerability database by Volerion and is not affiliated with or endorsed by NIST or NVD.

CVE-2026-88008 Details

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.

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:9.1 CRITICALVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.

URL	Source(s)	Tag(s)
https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3	[email protected]	Patch
https://github.com/traefik/traefik/pull/13797	[email protected]	Issue TrackingPatch
https://github.com/traefik/traefik/releases/tag/v2.11.57	[email protected]	Release Notes
https://github.com/traefik/traefik/releases/tag/v3.7.13	[email protected]	Release Notes
https://github.com/traefik/traefik/security/advisories/GHSA-w4v4-9rw7-5326	[email protected]	PatchVendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-444	Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')	[email protected]
CWE-863	Incorrect Authorization	[email protected]

Affected Products

Product	Versions
traefik traefik	>= 2.11.26, < 2.11.57 >= 3.4.2, < 3.7.13
CPE cpe:2.3:a:traefik:traefik:::::::: Remediation No remediation found in references.

Change History

3 change records found show changes

Date	Action	Recorded By
Sep 14, 2026	Initial Analysis	[email protected]
Sep 10, 2026	CVE Modified	CISA-ADP
Sep 10, 2026	New CVE Received	[email protected]