CVE-2026-7307

Summary

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 Software

VendorProductVersion RangeStatus
Red HatRed Hat build of Keycloak 26.226.2.16-1 < *unaffected
Red HatRed Hat build of Keycloak 26.226.2-21 < *unaffected
Red HatRed Hat build of Keycloak 26.226.2-21 < *unaffected
Red HatRed Hat build of Keycloak 26.426.4.12-1 < *unaffected
Red HatRed Hat build of Keycloak 26.426.4-17 < *unaffected
Red HatRed Hat build of Keycloak 26.426.4-17 < *unaffected

Weaknesses

  • CWE-1286: Improper Validation of Syntactic Correctness of Input

Workarounds

To mitigate this vulnerability, restrict network access to the Keycloak SAML endpoint to trusted networks and clients. Implement firewall rules to limit inbound connections to the Keycloak service port (e.g., 8080) from untrusted sources. If the SAML protocol is not required for your deployment, consider disabling it to eliminate the attack surface. Applying these network restrictions or configuration changes may necessitate a restart or reload of the Keycloak service, which could temporarily affect its availability.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

keycloak: Keycloak: Denial of Service via specially crafted SAML input

Additional References

References