Vulnerability in mod_cluster's AdvertiseListenerImpl (CVE-2026-76166)
Summary
Vulnerability in mod_cluster's AdvertiseListenerImpl (CVE-2026-76166). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
A flaw was found in mod_cluster's AdvertiseListenerImpl (org.jboss.modcluster core module). A single crafted UDP multicast datagram with a valid HTTP status line and a "Server:" header but without the "Date:", "Digest:", and "Sequence:" headers triggers a NullPointerException in verifyDigest() that is not caught by the worker thread's exception handler. This causes the advertise listener thread to terminate permanently. The failure is silent (isListening() continues to return true) and persists until the node is restarted. The crash occurs before the AdvertiseSecurityKey comparison, so deployments with a configured security key are still affected.
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-2026-76166 has been found in mod_cluster's AdvertiseListenerImpl.
Risk of unauthorized operations or information disclosure. CVSS score: 4.3/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "mod_cluster's AdvertiseListenerImpl CVE-2026-76166" on the vendor's site.
CVE-2026-76166 (mod_cluster's AdvertiseListenerImpl) — CWE-476 / CVSS v3 4.3
Attack vector: adjacent-network / 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-476) exists in mod_cluster's AdvertiseListenerImpl.
Check the vendor advisory for the affected versions of mod_cluster's AdvertiseListenerImpl.
Severity: Medium (CVSS 4.3/10). 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. Audit SBOM/dependencies 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
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで mod_cluster's AdvertiseListenerImpl を使っているサービスとバージョンを洗い出す。
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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
- web secalert@redhat.com
- web secalert@redhat.com
- web nvd.nist.gov
- web github.com