CVE-2025-10044: Keycloak: keycloak error_description injection on error pages

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-09-05 · updated 2026-10-18
Weakness: CWE-79

Description

A flaw was found in Keycloak. Keycloak’s account console and other pages accept arbitrary text in the error_description query parameter. This text is directly rendered in error pages without validation or sanitization. While HTML encoding prevents XSS, an attacker can craft URLs with misleading messages (e.g., fake support phone numbers or URLs), which are displayed within the trusted Keycloak UI. This creates a phishing vector, potentially tricking users into contacting malicious actors.

Affected products

Red Hat build of Keycloak 26.4: all versions — fixed in 26.0-21, 26.0-22, 26.0.17-1, 26.2-9, 26.2.9-1
Keycloak: before 26.2.9 — fixed in 26.2.9

How to fix

Upgrade to a fixed version: Red Hat build of Keycloak 26.4 26.0-21, 26.0-22, 26.0.17-1, 26.2-9; Keycloak 26.2.9. Check the vendor advisory for mitigations.

References

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