CVE-2026-7307

Keycloak: keycloak: denial of service via specially crafted saml input

Published May 19, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

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.

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-p5mv-gj8j-xqgf Keycloak: Denial of Service via specially crafted SAML input
History
Type Values Removed Values Added
CPEs cpe:/a:redhat:red_hat_single_sign_on:7.6::el7
References
Type Values Removed Values Added
CPEs cpe:/a:redhat:red_hat_single_sign_on:7.6::el8
cpe:/a:redhat:red_hat_single_sign_on:7.6::el9
References
Type Values Removed Values Added
First Time appeared Redhat rhosemc
CPEs cpe:/a:redhat:red_hat_single_sign_on:7 cpe:/a:redhat:red_hat_single_sign_on:7.6
cpe:/a:redhat:rhosemc:1.0::el8
Vendors & Products Redhat rhosemc
References
Type Values Removed Values Added
First Time appeared Redhat red Hat Single Sign On
CPEs cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat red Hat Single Sign On
Type Values Removed Values Added
CPEs cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*
Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak: cpe:/a:redhat:build_keycloak:26.2::el9
cpe:/a:redhat:build_keycloak:26.4::el9
References
Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
Vendors & Products Redhat build Of Keycloak
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Oct 6, 2026, 4:43 PM
Reserved
Apr 28, 2026, 11:51 AM
Status
Modified
Published
May 19, 2026, 12:16 PM
Modified
Oct 26, 2026, 1:10 PM
Severity
Important
Public date
May 19, 2026, 10:42 AM