CVE-2026-37982: redhat build_of_keycloak Authentication Bypass by Capture-replay

Vulnerability summary

CVE-2026-37982 is a medium (CVSS 6.8) Authentication Bypass by Capture-replay vulnerability in redhat build_of_keycloak. EPSS estimates a 0.57% chance of exploitation in the next 30 days, higher than 46.3% of scored vulnerabilities.

Timeline

1. 19-05-2026
   PublishedVulnerability first disclosed.
2. 20-05-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in Keycloak. This authentication vulnerability allows a remote attacker to replay `ExecuteActionsActionToken` tokens within Keycloak's WebAuthn (Web Authentication) flow. By intercepting an execute-actions email link, an attacker can register their own authenticator to a victim's account. This leads to unauthorized enrollment of a hardware-backed credential, enabling persistent account takeover.

• CWE-294Authentication Bypass by Capture-replayA capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).