CVE record · CVE-2026-76166

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

CVSS 4.3 MediumEPSS 0.027 · 86th percentile

Published by the CVE Program (CNA: redhat) at 19 Aug 2026, 10:01 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
Red Hat	Red Hat JBoss Web Server 7.0.3 Package name: mod_cluster-core https://access.redhat.com/downloads/content/package-browser/	No versions given Other versions: unaffected
Red Hat	Red Hat JBoss Web Server 7.0 on RHEL 10 Package name: jws7-mod_cluster https://access.redhat.com/downloads/content/package-browser/	unaffected 0:2.1.1-1.Final_redhat_00001.1.el10jws to before * rpm Other versions: affected
Red Hat	Red Hat JBoss Web Server 7.0 on RHEL 10 Package name: jws7-tomcat https://access.redhat.com/downloads/content/package-browser/	unaffected 0:11.0.21-10.redhat_00010.1.el10jws to before * rpm Other versions: affected
Red Hat	Red Hat JBoss Web Server 7.0 on RHEL 10 Package name: jws7-tomcat-native https://access.redhat.com/downloads/content/package-browser/	unaffected 0:1.3.7-4.redhat_4.el10jws to before * rpm Other versions: affected
Red Hat	Red Hat JBoss Web Server 7.0 on RHEL 8 Package name: jws7-mod_cluster https://access.redhat.com/downloads/content/package-browser/	unaffected 0:2.1.1-1.Final_redhat_00001.1.el8jws to before * rpm Other versions: affected
Red Hat	Red Hat JBoss Web Server 7.0 on RHEL 8 Package name: jws7-tomcat https://access.redhat.com/downloads/content/package-browser/	unaffected 0:11.0.21-10.redhat_00010.1.el8jws to before * rpm Other versions: affected
Red Hat	Red Hat JBoss Web Server 7.0 on RHEL 8 Package name: jws7-tomcat-native https://access.redhat.com/downloads/content/package-browser/	unaffected 0:1.3.7-4.redhat_4.el8jws to before * rpm Other versions: affected
Red Hat	Red Hat JBoss Web Server 7.0 on RHEL 9 Package name: jws7-mod_cluster https://access.redhat.com/downloads/content/package-browser/	unaffected 0:2.1.1-1.Final_redhat_00001.1.el9jws to before * rpm Other versions: affected
Red Hat	Red Hat JBoss Web Server 7.0 on RHEL 9 Package name: jws7-tomcat https://access.redhat.com/downloads/content/package-browser/	unaffected 0:11.0.21-10.redhat_00010.1.el9jws to before * rpm Other versions: affected
Red Hat	Red Hat JBoss Web Server 7.0 on RHEL 9 Package name: jws7-tomcat-native https://access.redhat.com/downloads/content/package-browser/	unaffected 0:1.3.7-4.redhat_4.el9jws to before * rpm Other versions: affected
Red Hat	Red Hat JBoss Enterprise Application Platform 7 Package name: mod_cluster-core https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	No versions given Other versions: affected
Red Hat	Red Hat JBoss Enterprise Application Platform 8 Package name: mod_cluster-core https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	No versions given Other versions: affected
Red Hat	Red Hat JBoss Enterprise Application Platform Expansion Pack Package name: mod_cluster-core https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	No versions given Other versions: affected
Red Hat	Red Hat JBoss Web Server 5 Package name: mod_cluster-core https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	No versions given Other versions: unknown
Red Hat	Red Hat JBoss Web Server 6 Package name: mod_cluster-core https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	No versions given Other versions: affected
Red Hat	Red Hat Single Sign-On 7 Package name: mod_cluster-core https://access.redhat.com/downloads/content/package-browser/	No versions given Other versions: affected

Identifiers: CVE-2026-76166
CNA: redhat
Weakness (CWE): CWE-476
Tags: Red Hat JBoss Web Server 7.0.3
Red Hat JBoss Web Server 7.0 on RHEL 10
Red Hat JBoss Web Server 7.0 on RHEL 8
Red Hat JBoss Web Server 7.0 on RHEL 9
Red Hat JBoss Enterprise Application Platform 7
Red Hat JBoss Enterprise Application Platform 8
Red Hat JBoss Enterprise Application Platform Expansion Pack
Red Hat JBoss Web Server 5
Memory corruption
Published: 19 Aug 2026
Updated: 3 Nov 2026

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
4.3	Medium	3.1	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L	CNA (redhat)

CISA KEV Not listed.
EPSS 0.027, the 86th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

19 Aug 2026, 10:01 UTC Confirmed by the CVE List
19 Aug 2026, 10:16 UTC Confirmed by NVD

Sources

References from the CNA

access.redhat.com/errata/RHSA-2026:93618 vendor-advisoryredhat
access.redhat.com/errata/RHSA-2026:93622 vendor-advisoryredhat
access.redhat.com/security/cve/CVE-2026-76166 vdb-entryredhat
bugzilla.redhat.com/show_bug.cgi?id=2510883 issue-trackingredhat

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.