CVE-2026-110931 (GCVE-0-2026-110931)
Vulnerability from cvelistv5
Published
2026-11-05 16:04
Modified
2026-11-06 19:55
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-835 - Loop with Unreachable Exit Condition
Summary
A flaw was found in the SAML 1.1 assertion parser of Keycloak, a tool used for identity and access management. The issue occurs when the parser handles a specific element called AuthorityBinding within an authentication statement. Due to an incomplete fix for a previous vulnerability, the parser can enter an infinite loop that consumes all available memory, causing the entire Keycloak service to crash and become unavailable to users.
References
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Impacted products
| Vendor | Product | Version | |||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.4 |
Unaffected: 26.4.17-2 < * cpe:/a:redhat:build_keycloak:26.4::el9 |
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"value": "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.\n\n--- CME Mitigation Guidance (2026-11-06) ---\nDisclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.\n\nThe highest-value action is to advance parser state past AuthorityBinding elements during SAML 1.1 AuthenticationStatement processing in keycloak-saml-core to halt unbounded heap allocation: upgrade to Keycloak 26.4.17, 26.6.8 (or the fixed Rhbk/Keycloak Rhel/Keycloak Services builds), which advance the parser past AuthorityBinding child elements during SAML 1.1 AuthenticationStatement processing, closing all 2 injection vectors (crafted SAML request to realm SAML endpoint, crafted SAML request to SAML identity provider broker endpoint). Until patched, this is a concern on Keycloak deployments exposing realm SAML endpoints or SAML identity provider broker endpoints, so Restrict network access to Keycloak realm SAML endpoints and SAML identity provider broker endpoints to trusted networks and identity providers. As a compensating measure, Configure systemd WatchdogSec and Restart directives to automatically restart Keycloak following JVM OutOfMemoryError termination and Monitor cgroup memory.events and PSI metrics to detect anomalous memory pressure and rapid heap exhaustion. These controls limit blast radius and contain exploitation, but they do not fix the underlying SAML 1.1 parser infinite loop defect \u2014 apply the upstream patch to fully remediate.\n\nHighest-impact CME: CME-1204 Service Watchdog and Automatic Restart (systemd WatchdogSec/Restart) (medium)"
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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