Vulnerability in github.com/traefik/traefik/v3 (CVE-2026-54761)
Summary
Vulnerability in github.com/traefik/traefik/v3 (CVE-2026-54761). Confidential information can be exposed externally. Mitigation: upgrade to 3.6.21, 3.7.5 or later.
Original description
The description as published by the source.
Traefik is an HTTP reverse proxy and load balancer. Prior to 3.6.21 and 3.7.5, there is a high severity vulnerability in Traefik's Kubernetes Gateway provider affecting the crossProviderNamespaces allowlist. For HTTPRoute rules that declare multiple (WRR) backendRefs, Traefik evaluates the allowlist against the target backendRef.namespace instead of the route's own namespace. As a result, an HTTPRoute created in a namespace that is not allow-listed can reference a cross-provider TraefikService such as api@internal, dashboard@internal or rest@internal by pointing backendRef.namespace at an allow-listed namespace covered by a Gateway API ReferenceGrant, exposing internal Traefik services on the data plane. Exploitation requires the ability to create an accepted HTTPRoute and a matching ReferenceGrant from an allow-listed namespace; it does not require any change to Traefik static configuration, RBAC, or the deployment itself. This vulnerability is fixed in 3.6.21 and 3.7.5.
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-2026-54761 has been found in github.com/traefik/traefik/v3.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: upgrade github.com/traefik/traefik/v3 to 3.6.21, 3.7.5 or later.
If unsure, ask your IT team or search "github.com/traefik/traefik/v3 CVE-2026-54761" on the vendor's site.
CVE-2026-54761 (github.com/traefik/traefik/v3) — CWE-284 / CVSS v3 7.1
Attack vector: remote (network-reachable) / no user interaction
Patched: 3.6.21, 3.7.5 — 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-284) exists in github.com/traefik/traefik/v3.
Check the vendor advisory for the affected versions of github.com/traefik/traefik/v3.
Severity: High (CVSS 7.1/10). Confidential information can be exposed externally.
Update to 3.6.21, 3.7.5.
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/v3' . 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
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1Identify exposure identify
grep -r 'github.com/traefik/traefik/v3' . | 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/v3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/v3 to 3.6.21, 3.7.5ステージング環境で 3.6.21, 3.7.5 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。
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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。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- web github.com
- web github.com
- web github.com