VULNERABILITY INTELLIGENCE
CVE-2026-76166
CVSS score4.3 MEDIUM
EPSS probability1.03%
CISA KEVNot currently listed
Published2026-08-19
Last modified2026-08-20
CVSS vectorCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Description
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.
Weakness classification
- CWE-476: NULL Pointer Dereference