Vulnerability in Traefik (CVE-2026-26999)
Summary
Vulnerability in Traefik (CVE-2026-26999). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.38 and 3.6.9, there is a potential vulnerability in Traefik managing TLS handshake on TCP routers. When Traefik processes a TLS connection on a TCP router, the read deadline used to bound protocol sniffing is cleared before the TLS handshake is completed. When a TLS handshake read error occurs, the code attempts a second handshake with different connection parameters, silently ignoring the initial error. A remote unauthenticated client can exploit this by sending an incomplete TLS record and stopping further data transmission, causing the TLS handshake to stall indefinitely and holding connections open. By opening many such stalled connections in parallel, an attacker can exhaust file descriptors and goroutines, degrading availability of all services on the affected entrypoint. This issue has been patched in versions 2.11.38 and 3.6.9.
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-2026-26999 has been found in Traefik.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Traefik CVE-2026-26999" on the vendor's site.
CVE-2026-26999 (Traefik) — CWE-400 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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-400) exists in Traefik.
Check the vendor advisory for the affected versions of Traefik.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
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
-
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。 -
2Post-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 github.com
- advisory access.redhat.com
- advisory access.redhat.com
- advisory github.com
- advisory nvd.nist.gov
- report bugzilla.redhat.com
- web github.com
- web github.com
- web security.access.redhat.com