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CVE-2026-4636

Keycloak: keycloak: uma policy bypass allows authenticated users to gain unauthorized access to victim-owned resources.

Published: Apr 2, 2026Updated: Apr 16, 2026 Sources: CVE List NVD BDUCWE-551
NVD MITRE
8.1CVSSHIGH
EPSS Score
0.3%
Top 74.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA) policy validation. This allows the attacker to include resource identifiers owned by other users in a policy creation request, even if the URL path specifies an attacker-owned resource. Consequently, the attacker gains unauthorized permissions to victim-owned resources, enabling them to obtain a Requesting Party Token (RPT) and access sensitive information or perform unauthorized actions.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
Open in CVSS calculator →

Weaknesses

CWE-551

Affected Products

Red Hat build of Keycloak 26.2Red Hat
On-prem
Operating Systems / linux-distro
Red Hat build of Keycloak 26.2.15Red Hat
On-prem
Operating Systems / linux-distro
Red Hat build of Keycloak 26.4Red Hat
On-premWeb App
Web & CMS Plugins
Red Hat build of Keycloak 26.4.11Red Hat
On-prem
Operating Systems / linux-distro
АЛЬТ СП 10АО «ИВК»
On-premOS
Operating Systems / linux-distro
red hatcommercialUSOperating Systemsaka red hat
ао «ивк»commercialRUOperating Systemsaka ivk
and 3 more affected products View all →

Exploitability

Official Patch Available
Workaround Available

References

https://access.redhat.com/errata/RHSA-2026:6475
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:6476
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:6477
access.redhat.com
and 8 more references View all →

Timeline

Published
Apr 2, 2026
Last Updated
Apr 16, 2026

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