Log in Start free

Vulnerability · Published Jan 15, 2026 · Assigned by redhat

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

Low 3.7

In plain English

A low-severity improper input validation in Red Hat Build of Keycloak from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities).

Severity (CVSS 3.1)3.7Low
Exploit odds (30 days)0.5%top 57.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Mavenorg.keycloak:keycloak-quarkus-serverno fix listedGHSA-v897-pv23-r8cw

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat build of Keycloak 26.4.9 see references
Red Hat Red Hat Build of Keycloak see references
Red Hat Red Hat JBoss Enterprise Application Platform 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack see references
Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack see references
Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack see references

Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

References