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.

The remote Redhat Enterprise Linux 10 / 8 / 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:96228 advisory.

    Red Hat JBoss Web Server is a fully integrated and certified set of components for hosting Java web     applications. It is comprised of the Apache Tomcat Servlet container, JBoss HTTP Connector (mod_cluster),     the PicketLink Vault extension for Apache Tomcat, and the Tomcat Native library.

    This release of Red Hat JBoss Web Server 6.2.6 serves as a replacement for Red Hat JBoss Web Server 6.2.5.
    This release includes bug fixes, enhancements and component upgrades, which are documented in the Release     Notes that are linked to in the References section.

    Security Fix(es):

    * mod_cluster-core: mod_cluster Advertise Listener: unauthenticated DoS via crafted multicast datagram     (CVE-2026-76166)
    * jws6-tomcat-native: Apache Tomcat Native: Client certificate verification requirements can be down-     graded via race condition (CVE-2026-86247)
    * jws6-tomcat: Apache Tomcat: Denial of Service via AJP request (CVE-2026-78383)
    * jws6-tomcat: Apache Tomcat: Denial of Service via busy wait during WebSocket close (CVE-2026-77791)
    * jws6-tomcat: Apache Tomcat: HTTP/2 request smuggling due to header mix-up (CVE-2026-86350)
    * jws6-tomcat: Apache Tomcat: Authentication Bypass in WebSocket Endpoints (CVE-2026-76183)
    * jws6-tomcat: Apache Tomcat: Denial of Service due to lost asynchronous WebSocket write timeouts     (CVE-2026-79677)
    * jws6-tomcat: Apache Tomcat: TLS implementations ignore Certificate Revocation Lists (CVE-2026-73581)
    * jws6-tomcat: Apache Tomcat: OCSP checks sometimes soft-fail with FFM even when soft-fail is disabled     (CVE-2026-86248)
    * jws6-tomcat-native: Apache Tomcat Native: Denial of Service via buffer over-read during TLS handshake     (CVE-2026-86243)
    * jws6-tomcat-native: Apache Tomcat Native: Weakened TLS connection security via insecure default     configuration (CVE-2026-86246)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 10 / 8 / 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:93618 advisory.

    Red Hat JBoss Web Server is a fully integrated and certified set of components for hosting Java web     applications. It is comprised of the Apache Tomcat Servlet container, JBoss HTTP Connector (mod_cluster),     the PicketLink Vault extension for Apache Tomcat, and the Tomcat Native library.

    This release of Red Hat JBoss Web Server 7.0.3 serves as a replacement for Red Hat JBoss Web Server 7.0.2.
    This release includes bug fixes, enhancements and component upgrades, which are documented in the Release     Notes that are linked to in the References section.

    Security Fix(es):

    * mod_cluster-core: mod_cluster Advertise Listener: unauthenticated DoS via crafted multicast datagram     (CVE-2026-76166)
    * jws7-tomcat-native: Apache Tomcat Native: Client certificate verification requirements can be down-     graded via race condition (CVE-2026-86247)
    * jws7-tomcat: Apache Tomcat: Denial of Service via AJP request (CVE-2026-78383)
    * jws7-tomcat: Apache Tomcat: Denial of Service via busy wait during WebSocket close (CVE-2026-77791)
    * jws7-tomcat: Apache Tomcat: HTTP/2 request smuggling due to header mix-up (CVE-2026-86350)
    * jws7-tomcat: Apache Tomcat: Authentication Bypass in WebSocket Endpoints (CVE-2026-76183)
    * jws7-tomcat: Apache Tomcat: Denial of Service due to lost asynchronous WebSocket write timeouts     (CVE-2026-79677)
    * jws7-tomcat: Apache Tomcat: TLS implementations ignore Certificate Revocation Lists (CVE-2026-73581)
    * jws7-tomcat: Apache Tomcat: OCSP checks sometimes soft-fail with FFM even when soft-fail is disabled     (CVE-2026-86248)
    * jws7-tomcat-native: Apache Tomcat Native: Denial of Service via buffer over-read during TLS handshake     (CVE-2026-86243)
    * jws7-tomcat-native: Apache Tomcat Native: Weakened TLS connection security via insecure default     configuration (CVE-2026-86246)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Type	Severity
377743	RHEL 10 / 8 / 9 : Red Hat JBoss Web Server 6.2.6 (RHSA-2026:96228)	Nessus	Red Hat Local Security Checks	Local	critical
375539	RHEL 10 / 8 / 9 : Red Hat JBoss Web Server 7.0.3 (RHSA-2026:93618)	Nessus	Red Hat Local Security Checks	Local	critical

Detections

Analytics

CVE-2026-76166

medium

Tenable Plugins

critical

critical