SB2026091074 - Multiple vulnerabilities in Red Hat build of Keycloak 26.2

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Main Vulnerability Database SB2026091074

SB2026091074 - Multiple vulnerabilities in Red Hat build of Keycloak 26.2

Published: September 10, 2026

Security Bulletin ID SB2026091074
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 3
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 67% Low 33%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 3 vulnerabilities.


1) Improper Validation of Syntactic Correctness of Input (CVE-ID: CVE-2026-7307)

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

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper validation of syntactic correctness of input in the SAML endpoint when processing specially crafted XML input. A remote attacker can send a specially crafted XML input to cause a denial of service.

The malicious input can cause high CPU usage and worker thread starvation, making the server unavailable.


2) Authentication Bypass by Spoofing (CVE-ID: CVE-2026-7507)

CWE-ID: CWE-290 - Authentication Bypass by Spoofing

CVSSv4: 7.1 [CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to take over accounts.

The vulnerability exists due to authentication bypass by spoofing in Keycloak login-actions endpoints when processing a crafted link to the /login-actions/restart endpoint. A remote attacker can pre-create an authentication session and trick a victim into visiting the crafted link to take over accounts.

User interaction is required to visit the crafted link.


3) Open redirect (CVE-ID: CVE-2026-7504)

CWE-ID: CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')

CVSSv4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to redirect users to unauthorized URLs.

The vulnerability exists due to improper URL validation in Keycloak\'s redirect URI validation logic when processing a malicious redirect URL containing multiple @ characters in the user-info component. A remote attacker can send a crafted redirect request to redirect users to unauthorized URLs.

User interaction is required, and only clients configured with a wildcard (*) in the Valid Redirect URIs field are affected.


Remediation

Install update from vendor's website.

References