What’s Vulnerable › Vulnerabilities

CVE-2026-0976: Org.keycloak/keycloak-quarkus-server: keycloak: proxy bypass due to improper handling of matrix parameters in url paths

• Severity: low (CVSS 3.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-15 · updated 2026-10-22
• Weakness: CWE-20

Description

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.

Affected products

• Red Hat build of Keycloak 26.4: all versions
• Red Hat JBoss Enterprise Application Platform 8: all versions
• Red Hat JBoss Enterprise Application Platform Expansion Pack: all versions

References

• https://access.redhat.com/errata/RHSA-2026:2365
• https://access.redhat.com/security/cve/CVE-2026-0976
• https://bugzilla.redhat.com/show_bug.cgi?id=2429869

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