Red Hat build of Keycloak 26.2: Excessive Platform Resource Consumption within a Loop
CVE-2026-4634 is a high-severity excessive platform resource consumption within a loop vulnerability in Red Hat build of Keycloak 26.2 from Red Hat, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.64% chance of exploitation within 30 days, higher than 51% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Red Hat build of Keycloak 26.2 you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on access.redhat.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.2 | Not specified in the record | Not stated |
| Red Hat | Red Hat build of Keycloak 26.2.15 | Not specified in the record | Not stated |
| Red Hat | Red Hat build of Keycloak 26.4 | Not specified in the record | Not stated |
| Red Hat | Red Hat build of Keycloak 26.4.11 | Not specified in the record | Not stated |
| Red Hat | Red Hat Single Sign-On 7.6.13 | Not specified in the record | Not stated |
| Red Hat | Red Hat Single Sign-On 7.6 for RHEL 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Single Sign-On 7.6 for RHEL 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Single Sign-On 7.6 for RHEL 9 | Not specified in the record | Not stated |
| Red Hat | RHEL-8 based Middleware Containers | Not specified in the record | Not stated |
| Red Hat | Build Of Keycloak | 26.2; 26.2.15; 26.4; 26.4.11 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (redhat.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (redhat.com) |
| CVSS 3.1 | 7.5 | High | CNA |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Excessive Platform Resource Consumption within a Loop
The product has a loop body or loop condition that contains a control element that directly or indirectly consumes platform resources, e.g. messaging, sessions, locks, or file descriptors.
More Excessive Platform Resource Consumption within a Loop vulnerabilities (CWE-1050)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other references
Other vulnerabilities in Red Hat build of Keycloak 26.2
- 7.5 High severity
- 8.1 High severity
- 7.5 High severity
- 8.1 High severity
- 7.4 High severity
- 7.3 High severity
Recent Excessive Platform Resource Consumption within a Loop vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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