CVE-2026-7307: Keycloak: keycloak: denial of service via specially crafted saml input

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-19 · updated 2026-10-26
Weakness: CWE-1286

Description

A flaw was found in Keycloak. A remote, unauthenticated attacker can send a specially crafted XML input to the Security Assertion Markup Language (SAML) endpoint. This malicious input can cause high CPU usage and worker thread starvation, leading to a Denial of Service (DoS) where the server becomes unavailable.

Affected products

Red Hat build of Keycloak 26.4: from 26.4 before 26.4.12 — fixed in 26.4.12

How to fix

Upgrade to a fixed version: Red Hat build of Keycloak 26.4 26.4.12. Check the vendor advisory for mitigations.

References

https://access.redhat.com/errata/RHSA-2026:19594
https://access.redhat.com/errata/RHSA-2026:19595
https://access.redhat.com/errata/RHSA-2026:19596
https://access.redhat.com/errata/RHSA-2026:19597
https://access.redhat.com/errata/RHSA-2026:76128
https://access.redhat.com/errata/RHSA-2026:76129
https://access.redhat.com/errata/RHSA-2026:76130
https://access.redhat.com/errata/RHSA-2026:76132
https://access.redhat.com/errata/RHSA-2026:76134
https://access.redhat.com/security/cve/CVE-2026-7307
https://bugzilla.redhat.com/show_bug.cgi?id=2476526
https://access.redhat.com/errata/RHSA-2026:19594

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