Keycloak: keycloak: uma policy bypass allows authenticated users to gain unauthorized access to victim-owned resources.
Summary
| CVE | CVE-2026-4636 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-04-02 13:16:27 UTC |
| Updated | 2026-04-02 17:16:30 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 8.1 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Problem Types: CWE-551 | CWE-551 Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 8.1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N |
| 3.1 | CNA | CVSS | 8.1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Build Of Keycloak 26.2 | unaffected 26.2.15-1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.2 | unaffected 26.2-18 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.2 | unaffected 26.2-18 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.2.15 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4 | unaffected 26.4.11-1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4 | unaffected 26.4-14 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4 | unaffected 26.4-14 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4.11 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/security/cve/CVE-2026-4636 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:6478 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:6476 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:6475 | [email protected] | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/errata/RHSA-2026:6477 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-03-23T08:15:12.427Z | Reported to Red Hat. |
| CNA | 2026-04-02T12:30:00.000Z | Made public. |
Workarounds
CNA: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
There are currently no legacy QID mappings associated with this CVE.