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.

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Advisories

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Fixes

Solution

No solution given by the vendor.


Workaround

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.

History

Tue, 19 May 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Tue, 19 May 2026 11:30:00 +0000

Type Values Removed Values Added
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.
Title Keycloak: keycloak: denial of service via specially crafted saml input
First Time appeared Redhat
Redhat build Keycloak
Weaknesses CWE-1286
CPEs cpe:/a:redhat:build_keycloak:
Vendors & Products Redhat
Redhat build Keycloak
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-05-19T10:52:24.684Z

Reserved: 2026-04-28T11:51:30.176Z

Link: CVE-2026-7307

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-19T12:16:19.423

Modified: 2026-05-19T12:16:19.423

Link: CVE-2026-7307

cve-icon Redhat

Severity : Important

Publid Date: 2026-05-19T10:42:34Z

Links: CVE-2026-7307 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-19T12:30:05Z

Weaknesses