SB2026090158 - Multiple vulnerabilities in Red Hat build of Keycloak 26.4



SB2026090158 - Multiple vulnerabilities in Red Hat build of Keycloak 26.4

Published: September 1, 2026

Security Bulletin ID SB2026090158
CSH Severity
High
Patch available
YES
Number of vulnerabilities 2
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

High 50% Low 50%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 2 vulnerabilities.


1) Weak Password Recovery Mechanism for Forgotten Password (CVE-ID: CVE-2026-18963)

CWE-ID: CWE-640 - Weak password recovery mechanism

CVSSv4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to take over arbitrary user accounts.

The vulnerability exists due to a weak password recovery mechanism in the reset-credentials flow of the keycloak-services component when handling password reset requests. A remote attacker can bypass the required email verification link and set new credentials to take over arbitrary user accounts.


2) Uncontrolled Recursion (CVE-ID: CVE-2026-13757)

CWE-ID: CWE-674 - Uncontrolled Recursion

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/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 uncontrolled recursion in the p11_rpc_message_get_attribute and p11_rpc_message_get_attribute_array_value functions when processing nested template attributes. A remote attacker can send a specially crafted request with deeply nested attributes via the RPC Unix domain socket to cause a denial of service.

Exploitation can lead to stack exhaustion and crash the server process.


Remediation

Install update from vendor's website.