CVE-2026-76166
MediumCVSS 4.3Summary
In mod_cluster's AdvertiseListenerImpl, a single crafted UDP multicast datagram with a valid HTTP status line and a "Server:" header but without "Date:", "Digest:", and "Sequence:" headers triggers a NullPointerException in verifyDigest() that is not caught. This causes the advertise listener thread to terminate permanently, and the failure is silent (isListening() continues to return true) until the node is restarted.
Risk Assessment
The risk includes permanent failure of advertise listening in the cluster, which can lead to service unavailability and inability to automatically discover nodes.
Recommendation
Apply the patch to mod_cluster that addresses the unhandled exception. Restart nodes after the update to restore listening.
Original NVD description (English 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.