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Advisory severityLow3.7Red Hat Linux

Low [CVE-2026-0976] proxy bypass due to improper handling of matrix parameters in url paths

This low-severity Red Hat Linux advisory covers CVE-2026-0976 affecting Red Hat Build of Keycloak, Red Hat JBoss Enterprise Application Platform 8, Red Hat JBoss Enterprise Application Platform Expansion Pack.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-0976 Source published Source updated

VulniPulse record published

CVE-2026-0976
Affected products & platforms
Red Hat LinuxUnclassified
Open source advisory

Summary

A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them.

A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable.

This vulnerability is rated Low for Red Hat Keycloak. The flaw arises from Keycloak's acceptance of RFC-compliant matrix parameters in URL paths, which can be mishandled by certain reverse proxy configurations.

Exploitation depends on the specific reverse proxy configuration. Red Hat severity: Low — CVSS 3.7 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N).

Weakness: CWE-20. Affected Red Hat products: Red Hat Build of Keycloak; Red Hat JBoss Enterprise Application Platform 8; Red Hat JBoss Enterprise Application Platform Expansion Pack.

Red Hat does not currently list a fixing RHSA for this CVE.

Is CVE-2026-0976 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-0976 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-0976?

The advisory VulniPulse tracks names no fixed release. Follow Red Hat's guidance for workarounds and updates.

Confirm against the vendor advisory before you patch.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · high-confidence parse· fetched 3 months ago·verify at source

Fixed versions

No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.

Official advisory · high-confidence parse· fetched 3 months ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • To mitigate this issue, ensure that all administrative and sensitive endpoints within Keycloak are adequately protected by robust authentication and authorization policies, independent of any reverse proxy path filtering. Operators should review Keycloak's internal access controls to confirm that access to these endpoints is restricted to authorized users and roles.

Official advisory · high-confidence parse· fetched 3 months ago·verify at source

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