Vulnerability in Traefik (CVE-2026-88878)
Summary
Vulnerability in Traefik (CVE-2026-88878). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 2.11.56 or later.
Original description
The description as published by the source.
Traefik is an HTTP reverse proxy and load balancer. In versions >= v2.8.2 through <= v2.11.55 and >= v3.0.0 through <= v3.7.11, the entryPoints..transport.respondingTimeouts settings — notably readTimeout, which is enabled by default at 60s — are not applied to the HTTP/3 request path. readTimeout is enforced as a deadline on the underlying TCP connection, which cannot be applied to a QUIC stream, and Traefik's HTTP/3 server is constructed without any timeout. As a result, on entry points with HTTP/3 enabled, an unauthenticated remote client that trickles request body bytes can hold a request open indefinitely and, with it, one upstream connection per request, exhausting bounded backend connection pools and causing denial of service. The issue was introduced in v2.8.2 when a quic-go API change removed the embedded http.Server that carried these timeouts. Fixed in v2.11.56 and v3.7.12.
Source: NIST National Vulnerability Database 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-2026-88878 has been found in Traefik.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade Traefik to 2.11.56 or later.
If unsure, ask your IT team or search "Traefik CVE-2026-88878" on the vendor's site.
CVE-2026-88878 (Traefik) — CWE-770 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 2.11.56 — 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-770) exists in Traefik.
Check the vendor advisory for the affected versions of Traefik.
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.
Update to 2.11.56.
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 'Traefik' . 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 'Traefik' . | 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
Traefik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 Traefik to 2.11.56ステージング環境で 2.11.56 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。
References
- advisory disclosure@vulncheck.com
- patch disclosure@vulncheck.com
- web nvd.nist.gov
- web github.com