Traefik: lowercase `Connection` tokens can delete traefik-managed forwarded identity headers (for example, `X-Real-Ip`)

Summary

CVE	CVE-2026-29054
State	PUBLISHED
Assigner	GitHub_M
Source Priority	CVE Program / NVD first with legacy fallback
Published	2026-03-05 19:16:15 UTC
Updated	2026-06-30 03:18:06 UTC
Description	Traefik is an HTTP reverse proxy and load balancer. From version 2.11.9 to 2.11.37 and from version 3.1.3 to 3.6.8, there is a potential vulnerability in Traefik managing the Connection header with X-Forwarded headers. When Traefik processes HTTP/1.1 requests, the protection put in place to prevent the removal of Traefik-managed X-Forwarded headers (such as X-Real-Ip, X-Forwarded-Host, X-Forwarded-Port, etc.) via the Connection header does not handle case sensitivity correctly. The Connection tokens are compared case-sensitively against the protected header names, but the actual header deletion operates case-insensitively. As a result, a remote unauthenticated client can use lowercase Connection tokens (e.g. Connection: x-real-ip) to bypass the protection and trigger the removal of Traefik-managed forwarded identity headers. This issue has been patched in versions 2.11.38 and 3.6.9.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Problem Types: CWE-178 | CWE-178 CWE-178: Improper Handling of Case Sensitivity | CWE-178 Improper Handling of Case Sensitivity

Version	Source	Type	Score	Severity	Vector
3.1	ADP	CVSS	7.5	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`
3.1	[email protected]	Secondary	7.5	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`
3.1	0b0ca135-0b70-47e7-9f44-1890c2a1c46c	Secondary	7.5	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`
3.1	CNA	DECLARED	7.5	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`

CVSS v3.1 Breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

NVD Known Affected Configurations (CPE 2.3)

Type	Vendor	Product	Version	Update	Edition	Language
Application	Traefik	Traefik	All	All	All	All

Vendor Declared Affected Products

Source	Vendor	Product	Version	Platforms
CNA	Traefik	Traefik	affected >= 2.11.9, < 2.11.38	Not specified
CNA	Traefik	Traefik	affected >= 3.1.3, < 3.6.9	Not specified
ADP	Red Hat	Red Hat OpenShift Dev Spaces 3.27	Not specified	Not specified

References

Reference	Source	Link	Tags
github.com/traefik/traefik/releases/tag/v2.11.38	[email protected]	github.com	Product, Release Notes
github.com/traefik/traefik/releases/tag/v3.6.9	[email protected]	github.com	Product, Release Notes
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29054.json	0b0ca135-0b70-47e7-9f44-1890c2a1c46c	security.access.redhat.com
access.redhat.com/security/cve/CVE-2026-29054	0b0ca135-0b70-47e7-9f44-1890c2a1c46c	access.redhat.com
access.redhat.com/errata/RHSA-2026:10175	0b0ca135-0b70-47e7-9f44-1890c2a1c46c	access.redhat.com
bugzilla.redhat.com/show_bug.cgi	0b0ca135-0b70-47e7-9f44-1890c2a1c46c	bugzilla.redhat.com
github.com/traefik/traefik/security/advisories/GHSA-92mv-8f8w-wq52	[email protected]	github.com	Patch, Vendor Advisory
CVE Program record	CVE.ORG	www.cve.org	canonical
NVD vulnerability detail	NVD	nvd.nist.gov	canonical, analysis

No vendor comments have been submitted for this CVE.

Additional Advisory Data

Source	Time	Event
ADP	2026-03-05T19:01:04.119Z	Reported to Red Hat.
ADP	2026-03-05T16:18:49.230Z	Made public.

Solutions

ADP: RHSA-2026:10175: Red Hat OpenShift Dev Spaces 3.27

Workarounds

ADP: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

There are currently no legacy QID mappings associated with this CVE.