CVE-2026-18203
Keycloak-services: keycloak-services: group policy extendchildren matches sibling group path prefixes
MEDIUM 6.5
At a glance
- Source
- NVD
- EPSS
- EPSS 0.31 % · percentile 24 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- redhat
- NVD status
- Analyzed
Description
A flaw was found in the group policy evaluation logic of Keycloak, an identity and access management solution. When a group policy is set to extend permissions to child groups, the system incorrectly uses a simple text-based prefix check to verify group membership. This allows a user who belongs to a different group with a similar starting name to bypass security checks and gain unauthorized access to administrative functions or protected resources.
Weaknesses (CWE)
- CWE-863 — Incorrect Authorization
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N | redhat |
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N | NVD · secalert@redhat.com (Secondary) |
European references
- ENISA EUVD · EUVD-2026-51484
- GCVE · GCVE-0-2026-18203
Affected configurations (NVD CPE)
cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:-:*:*:*
Affected products
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |