Vulnerability in Apache Tomcat (CVE-2026-86247)
Summary
Vulnerability in Apache Tomcat (CVE-2026-86247). Confidential information can be exposed externally.
Original description
The description as published by the source.
Race condition within a thread vulnerability in Apache Tomcat Native allowed client certificate verification requirements to be down-graded for some configurations.
This issue affects Apache Tomcat Native: from 2.0.0 through 2.0.15, from 1.3.0 through 1.3.8. Unsupported versions may also be affected.
Users are recommended to upgrade to version 2.0.16 or 1.3.9, which fixes the issue.
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-2026-86247 has been found in Apache Tomcat.
Confidential information can be exposed externally. CVSS score: 7.4/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Apache Tomcat CVE-2026-86247" on the vendor's site.
CVE-2026-86247 (Apache Tomcat) — CWE-366 / CVSS v3 7.4
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-366) exists in Apache Tomcat.
Check the vendor advisory for the affected versions of Apache Tomcat.
Severity: High (CVSS 7.4/10). Confidential information can be exposed externally.
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 'Tomcat' . 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 'Tomcat' . | 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
Tomcat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 openwall.com
- patch security@apache.org
- web nvd.nist.gov
- web github.com