Vulnerability in github.com/traefik/traefik/v2 (CVE-2026-71325)
Summary
Vulnerability in github.com/traefik/traefik/v2 (CVE-2026-71325). Risk of unauthorized operations or information disclosure. Exploitable via TraefikService. Mitigation: upgrade to 2.11.54 or later.
Original description
The description as published by the source.
Summary
There is a medium severity vulnerability in Traefik's Kubernetes CRD provider. When providers.kubernetesCRD.allowCrossNamespace is disabled — the default — cross-namespace @kubernetescrd references are rejected for middlewares, TLS options and HTTP/TCP ServersTransports, but the same restriction was not applied to 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. Traefik v2 releases and the unmaintained v3 minor lines below v3.6 are affected and will not receive a patch on their own line; the remedy for those users is upgrading to a maintained, patched release.
Patches
- 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
For more information
If you have any questions or comments about this advisory, please open an issue.
Original Description
Summary
When providers.kubernetesCRD.allowCrossNamespace=false (the default), Traefik correctly rejects cross-namespace @kubernetescrd references for middlewares, TLS options, and HTTP/TCP ServersTransport, but it does not apply the same restriction to service…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-71325 has been found in github.com/traefik/traefik/v2.
Attackers can target a specific entry point like TraefikService over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.4/10.
What to do: upgrade github.com/traefik/traefik/v2 to 2.11.54 or later.
If unsure, ask your IT team or search "github.com/traefik/traefik/v2 CVE-2026-71325" on the vendor's site.
CVE-2026-71325 (github.com/traefik/traefik/v2) — CWE-653 / CVSS v3 4.4
Attack vector: local / no user interaction
Attack surface: TraefikService / ServersTransport / df00d82f / configBuilder.nameAndService
Patched: 2.11.54 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-653) exists in github.com/traefik/traefik/v2. Attackers reach the vulnerable code path via TraefikService.
Check the vendor advisory for the affected versions of github.com/traefik/traefik/v2. Attack surface: TraefikService / ServersTransport / df00d82f / configBuilder.nameAndService.
Severity: Medium (CVSS 4.4/10). Risk of unauthorized operations or information disclosure.
Update to 2.11.54.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/traefik/traefik/v2' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/traefik/traefik/v2' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/traefik/traefik/v2を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/traefik/traefik/v2 to 2.11.54ステージング環境で 2.11.54 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。