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Advisory details: vulnrichment / CVE-2026-4636
Advisory ID vulnrichment/CVE-2026-4636
Aliases
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (1)
CWE-551 Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
System Score Found at
cvssv3.1 8.1
ssvc Track
Reference id Reference type URL
https://access.redhat.com/errata/RHSA-2026:6475
https://access.redhat.com/errata/RHSA-2026:6476
cpe:/a:redhat:build_keycloak:26.2::el9 Other https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:/a:redhat:build_keycloak:26.2::el9
cpe:/a:redhat:build_keycloak:26.4::el9 Other https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:/a:redhat:build_keycloak:26.4::el9
CVE-2026-4636 Advisory https://access.redhat.com/security/cve/CVE-2026-4636
RHSA-2026:6477 Advisory https://access.redhat.com/errata/RHSA-2026:6477
RHSA-2026:6478 Advisory https://access.redhat.com/errata/RHSA-2026:6478
show_bug.cgi?id=2450251 Bug https://bugzilla.redhat.com/show_bug.cgi?id=2450251
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N Found at None
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:T/P:M/B:A/M:M/D:T/2026-04-02T13:13:39Z/ Found at None

Vector: SSVCv2/E:N/A:N/T:T/P:M/B:A/M:M/D:T/2026-04-02T13:13:39Z/

Decision: Track

Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2026/4xxx/CVE-2026-4636.json

Source Advisory: vulnrichment/CVE-2026-4636

View SSVC decision tree 
[{'Exploitation': 'none'},
 {'Automatable': 'no'},
 {'Technical Impact': 'total'},
 {'Mission Prevalence': 'minimal'},
 {'Public Well-being Impact': 'material'},
 {'Mission & Well-being': 'medium'}]