🔐 CVE Alert

CVE-2026-76166

MEDIUM 4.3

Modcluster-core: mod_cluster advertise listener: unauthenticated dos via crafted multicast datagram

CVSS Score
4.3
EPSS Score
0.0%
EPSS Percentile
0th

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.

CWE CWE-476
Vendor red hat
Product red hat jboss enterprise application platform 7
Published Aug 19, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

Affected Versions

Red Hat / Red Hat JBoss Enterprise Application Platform 7
All versions affected
Red Hat / Red Hat JBoss Enterprise Application Platform 8
All versions affected
Red Hat / Red Hat JBoss Enterprise Application Platform Expansion Pack
All versions affected
Red Hat / Red Hat JBoss Web Server 5
All versions affected
Red Hat / Red Hat JBoss Web Server 6
All versions affected
Red Hat / Red Hat JBoss Web Server 7
All versions affected
Red Hat / Red Hat Single Sign-On 7
All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗
access.redhat.com: https://access.redhat.com/security/cve/CVE-2026-76166 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2510883

Credits

Red Hat would like to thank Kien Pham (Ninh Thanh Cyber Security (NTCS)) and Ta Duc Thien (Ninh Thanh Cyber Security (NTCS)) for reporting this issue.