Quick answers
- Is CVE-2026-0976 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-0976 being exploited in the wild.
- How severe is CVE-2026-0976?
- Low severity, with a CVSS score of 3.7, published 15 January 2026.
- Which products and versions are affected?
- org.keycloak:keycloak-quarkus-server (Maven) <= 26.2.5, ECOSYSTEM:introduced=0,last_affected=26.2.5.
- Is there a fix for CVE-2026-0976?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-0976 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-0976?
- Check whether you run org.keycloak:keycloak-quarkus-server (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
This improper input validation vulnerability stems from Keycloak accepting matrix parameters (semicolon-delimited parameters in URL path segments) that comply with RFC specifications. However, many reverse proxy configurations do not correctly parse or filter these parameters, allowing an attacker to craft requests that mask sensitive path segments and evade proxy-level access controls. The vulnerability requires network access to a Keycloak instance deployed behind a vulnerable reverse proxy configuration; no authentication is required. An attacker can bypass path-based filtering to reach administrative or sensitive endpoints, potentially gaining unauthorized access to restricted functionality. Patched versions are available from the vendor.
Affected products
- Red Hat Keycloak
Identifiers
- CVE-2026-0976
- GHSA-v897-pv23-r8cw
Timeline
- 2026-01-15: disclosed