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OpenAdvisories
Medium · 4.8 CVE-2026-71325 EUVD-2026-54293GHSA-62fc-8686-hfmqGO-2026-6203

Traefik: `allowCrossNamespace=false` bypass via `@kubernetescrd` TraefikService backendRef

Published Aug 6, 2026 · Updated Aug 7, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
traefik traefik < 2.11.54, >= 3.0.0, < 3.6.25, >= 3.7.0, < 3.7.10 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
SLES for SAP 16.0 govulncheck-vulndb 0.0.20260827T195228-160000.1.1 SUSE-SU-2026:23625-1
SLES 16.0 govulncheck-vulndb 0.0.20260827T195228-160000.1.1 SUSE-SU-2026:23625-1
ReleasePackageFixed inAdvisory
openSUSE Leap 16.0 govulncheck-vulndb 0.0.20260827T195228-160000.1.1 openSUSE-SU-2026:21761-1

Affected packages

EcosystemPackageAffectedFixedRecord
Go github.com/traefik/traefik <= 1.7.34 — GHSA-62fc-8686-hfmq
Go github.com/traefik/traefik all versions — GO-2026-6203
Go github.com/traefik/traefik/v2 < 2.11.54 2.11.54 GHSA-62fc-8686-hfmq
Go github.com/traefik/traefik/v3 >= 3.0.0, < 3.6.25 3.6.25 GHSA-62fc-8686-hfmq
Go github.com/traefik/traefik/v3 >= 3.7.0, < 3.7.10 3.7.10 GHSA-62fc-8686-hfmq
Go github.com/traefik/traefik/v3 >= 3.0.0, < 3.6.25 · >= 3.7.0, < 3.7.10 3.6.25, 3.7.10 GO-2026-6203

Advisories 2

References