Keycloak: org.keycloak.authorization: keycloak: unauthorized resource modification due to improper access control

published 2026-03-23 7 mo ago modified 2026-10-22 17 d ago also GHSA-4pgc-gfrr-wcmg , EUVD-2026-14389

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits: 0; none known

A flaw was found in Keycloak. An improper Access Control vulnerability in Keycloak’s User-Managed Access (UMA) resource_set endpoint allows attackers with valid credentials to bypass the allowRemoteResourceManagement=false restriction. This occurs due to incomplete enforcement of access control checks on PUT operations to the resource_set endpoint. This issue enables unauthorized modification of protected resources, impacting data integrity.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-4628 updated 2026-10-22 cvss 4.3

keycloak: org.keycloak.authorization: Keycloak: Unauthorized resource modification due to improper access control

Red Hat Build of Keycloak keycloak-services
affected: workaround, no fix available
Red Hat build of Keycloak 26.4.12
fixed: vendor fix RHSA-2026:19596
Red Hat JBoss Enterprise Application Platform 8 keycloak-services Red Hat JBoss Enterprise Application Platform Expansion Pack keycloak-services Red Hat Single Sign-On 7 keycloak-services
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 7 mo ago (2026-03-25)

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
GitHub	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
maven	org.keycloak:keycloak-services	<=26.6.0	no fix listed

Affected products

Red Hat Red Hat build of Keycloak 26.4.12
Red Hat Red Hat Build of Keycloak
Red Hat Red Hat JBoss Enterprise Application Platform 8
Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack
Red Hat Red Hat Single Sign-On 7

Classification

Weakness

CWE-284 Improper Access Control

References

access.redhat.com /errata/RHSA-2026:19596
vendor-advisory, web
access.redhat.com /security/cve/CVE-2026-4628
vdb-entry, web, vendor-advisory
bugzilla.redhat.com /show_bug.cgi?id=2450240
issue-tracking, web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-4628
advisory
github.com /keycloak/keycloak
web

Sources

CVE List CVE-2026-4628
GitHub Advisory GHSA-4pgc-gfrr-wcmg
NVD CVE-2026-4628

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary