Red Hat Keycloak/Single Sign-On SAML 1.1 assertion parser infinite loop

Summaryinfo

A vulnerability was found in Red Hat Keycloak and Single Sign-On. It has been declared as problematic. This impacts an unknown function of the component SAML 1.1 assertion parser. Such manipulation leads to infinite loop. This vulnerability is listed as CVE-2026-110931. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in Red Hat Keycloak and Single Sign-On (version now known) and classified as problematic. Affected by this issue is some unknown processing of the component SAML 1.1 assertion parser. The manipulation with an unknown input leads to a infinite loop vulnerability. Using CWE to declare the problem leads to CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. Impacted is availability. CVE summarizes:

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.

The advisory is shared for download at access.redhat.com. This vulnerability is handled as CVE-2026-110931 since 10/15/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 11/05/2026). The MITRE ATT&CK project declares the attack technique as T1499.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• Red Hat

Name

• Keycloak
• Single Sign-On

License

• open-source

Website

• Vendor: https://www.redhat.com/

CPE 2.3info

• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion