CVE-2026-3872

Keycloak: keycloak: information disclosure due to redirect_uri validation bypass

Published Apr 2, 2026 CVSS 3.1 · 7.3 High EPSS < 1% KEV · Not listed
Description
A flaw was found in Keycloak. This issue allows an attacker, who controls another path on the same web server, to bypass the allowed path in redirect Uniform Resource Identifiers (URIs) that use a wildcard. A successful attack may lead to the theft of an access token, resulting in information disclosure.

Remediation

Vendor Workaround

To mitigate this vulnerability, avoid using wildcards in `redirect_uri` configurations within Keycloak. Restricting `redirect_uri` to explicit, fully qualified URIs prevents the bypass of validation logic. This configuration change may require a service restart or reload to take effect.

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-cjm2-j6cm-6p6m Keycloak: Redirect URI validation bypass via ..;/ path traversal in OIDC auth endpoint
History
Type Values Removed Values Added
CPEs cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.2.15:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.2:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.4.11:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.4:*:*:*:text-only:*:*:*
Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
CPEs cpe:/a:redhat:build_keycloak:26.2::el9
Vendors & Products Redhat build Of Keycloak
References
Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak: cpe:/a:redhat:build_keycloak:26.4::el9
References
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description A flaw was found in Keycloak. This issue allows an attacker, who controls another path on the same web server, to bypass the allowed path in redirect Uniform Resource Identifiers (URIs) that use a wildcard. A successful attack may lead to the theft of an access token, resulting in information disclosure.
Title Keycloak: keycloak: information disclosure due to redirect_uri validation bypass
First Time appeared Redhat
Redhat build Keycloak
Weaknesses CWE-601
CPEs cpe:/a:redhat:build_keycloak:
Vendors & Products Redhat
Redhat build Keycloak
References
Metrics cvssV3_1

{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Jul 15, 2026, 1:02 AM
Reserved
Mar 10, 2026, 9:25 AM
Status
Modified
Published
Apr 2, 2026, 1:16 PM
Modified
Oct 26, 2026, 9:10 PM
Severity
Important
Public date
Apr 2, 2026, 12:30 PM