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CVE-2026-42498 high CVSS 7.3

Information Disclosure in tomcat (CVE-2026-42498)

Summary

Vulnerability in tomcat (CVE-2026-42498). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 10.1.55, 11.0.22, 9.0.118 or later.

Original description

The description as published by the source.

Exposure of HTTP Authentication Header to unexpected hosts during WebSocket authentication vulnerability in Apache Tomcat.

This issue affects Apache Tomcat: from 11.0.0 through 11.0.21, from 10.1.0 through 10.1.54, from 9.0.2 through 9.0.117, from 8.5.24 through 8.5.100, from 7.0.83 through 7.0.109.

Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118, which fix 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-2026-42498 has been found in tomcat.
Risk of unauthorized operations or information disclosure. CVSS score: 7.3/10.
What to do: upgrade tomcat to 10.1.55, 11.0.22, 9.0.118 or later.
If unsure, ask your IT team or search "tomcat CVE-2026-42498" on the vendor's site.

CVE-2026-42498 (tomcat) — CWE-200 / CVSS v3 7.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 10.1.55, 11.0.22, 9.0.118 — 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.

❓ What is the problem

Information disclosure (CWE-200) exists in tomcat.

📍 Affected scope

Check the vendor advisory for the affected versions of tomcat.

🔥 Severity

Severity: High (CVSS 7.3/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 10.1.55, 11.0.22, 9.0.118.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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

  1. 1
    Identify 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。

  2. 2
    Apply patch patch 
    Upgrade tomcat to 10.1.55, 11.0.22, 9.0.118

    ステージング環境で 10.1.55, 11.0.22, 9.0.118 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。

  3. 3
    Post-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

Bitnami tomcat
[{"type":"SEMVER","events":[{"introduced":"10.0.0"},{"fixed":"10.1.55"},{"introduced":"11.0.0"},{"fixed":"11.0.22"},{"introduced":"9.0.0"},{"fixed":"9.0.118"}]}]
maven org.apache.tomcat.embed:tomcat-embed-core
[{"type":"ECOSYSTEM","events":[{"introduced":"11.0.0-M1"},{"fixed":"11.0.22"}]}]
maven org.apache.tomcat:tomcat
[{"type":"ECOSYSTEM","events":[{"introduced":"11.0.0-M1"},{"fixed":"11.0.22"}]}]
maven org.apache.tomcat:tomcat-catalina
[{"type":"ECOSYSTEM","events":[{"introduced":"11.0.0-M1"},{"fixed":"11.0.22"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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