CVE-2026-4634: Red Hat build of Keycloak 26.2 · Excessive Platform Resource Consumption within a Loop
Affects Red Hat build of Keycloak 26.2Source CVE Database V5
Not known to be exploited · CVSS 7.5 High : upgrade Red Hat build of Keycloak 26.2 to 26.2.15 soon.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 26.2.15
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 2 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade org.keycloak/keycloak to 26.2.15.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Mavenorg.keycloak/keycloakpkg:maven/org.keycloak/keycloakOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Red Hat has released an official fix in Red Hat build of Keycloak version 26.2.15. Users should upgrade to version 26.2.15 or later to remediate this vulnerability. Before applying the update, back up existing installations, including applications, configuration files, and databases. No other mitigations or workarounds are specified in the vendor advisory.
Description
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.
References
- access.redhat.com/errata/RHSA-2026:6475 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:6476 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:6477 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:6478 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-4634 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2450250 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4634.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:76132 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:76134 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:76129 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:76130 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:76128 (opens in a new tab)