CVE-2026-76166 (GCVE-0-2026-76166)

Vulnerability from cvelistv5 – Published: 2026-08-19 10:01 – Updated: 2026-08-19 10:01
VLAI
Title
Modcluster-core: mod_cluster advertise listener: unauthenticated dos via crafted multicast datagram
Summary
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.
Severity
4.3 (Medium)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE
  • CWE-476 - NULL Pointer Dereference
Assigner
References
URL Tags
https://access.redhat.com/security/cve/CVE-2026-76166 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2510883 issue-trackingx_refsource_REDHAT
Impacted products
Vendor Product Version CPE status
Red Hat Red Hat JBoss Enterprise Application Platform 7     cpe:/a:redhat:jboss_enterprise_application_platform:7
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Red Hat Red Hat JBoss Enterprise Application Platform 8     cpe:/a:redhat:jboss_enterprise_application_platform:8
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Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack     cpe:/a:redhat:jbosseapxp
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Red Hat Red Hat JBoss Web Server 5     cpe:/a:redhat:jboss_enterprise_web_server:5
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Red Hat Red Hat JBoss Web Server 6     cpe:/a:redhat:jboss_enterprise_web_server:6
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Red Hat Red Hat JBoss Web Server 7     cpe:/a:redhat:jboss_enterprise_web_server:7
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Red Hat Red Hat Single Sign-On 7     cpe:/a:redhat:red_hat_single_sign_on:7
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Date Public
2026-08-04 00:00
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.
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.