Vulnerability in Traefik (CVE-2026-88010)
Summary
Vulnerability in Traefik (CVE-2026-88010). Risk of unauthorized operations or information disclosure. Exploitable via singleflight.Group. Mitigation: upgrade to 3.7.13 or later.
Original description
The description as published by the source.
Summary
Traefik's BasicAuth middleware coalesces concurrent credential checks through a singleflight.Group to avoid hashing the same password many times at once. Since v3.6.11 the deduplication key was built from the submitted password plus the stored secret, so it depended on server state: a non-existent username collapsed onto one shared key while each configured username produced its own. Under attacker-controlled concurrency, a probe request arriving inside a leader request's in-flight window is served the leader's fast coalesced result when the username does not exist, but computes its own hash (slow) when the username exists — reintroducing, only in the concurrent case, the unauthenticated username-enumeration timing oracle that GHSA-g3hg-j4jv-cwfr had hardened for sequential probing. The fix derives the singleflight key from the submitted credentials (username and password) only, so it no longer depends on whether the account exists or on any stored secret. Traefik v2 is not affected: the v2.11 BasicAuth middleware does not use singleflight coalescing, and Digest authentication is not affected. The impact is limited to username enumeration; no credential disclosure or authentication bypass is possible.
The vulnerability originates on the v3.6 line, which has reached end of life; users on v3.6 or earlier v3.x must upgrade to v3.7.13 to receive the fix.
Patches
For more information
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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-2026-88010 has been found in Traefik.
Attackers can target a specific entry point like singleflight.Group over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Traefik to 3.7.13 or later.
If unsure, ask your IT team or search "Traefik CVE-2026-88010" on the vendor's site.
CVE-2026-88010 (Traefik) — CWE-208
Attack surface: singleflight.Group / checkPassword / singleflight / singleflight.Group.Do
Patched: 3.7.13 — 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-208) exists in Traefik. Attackers reach the vulnerable code path via singleflight.Group.
Check the vendor advisory for the affected versions of Traefik. Attack surface: singleflight.Group / checkPassword / singleflight / singleflight.Group.Do.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 3.7.13.
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 3.7.13ステージング環境で 3.7.13 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
- web github.com
- web github.com
- web github.com
- web github.com
- web nvd.nist.gov
- web github.com