CVE-2025-13591 — Username Enumeration via Authentication Endpoint in WSO2 Identity Server Allows User Account Discovery
The authentication endpoint of WSO2 Identity Server fails to provide a consistent system response when a username does not exist in the system, allowing attackers to differentia…
Published: 2026-10-19 · CVSS: 5.3 · CVSS 3.1
The authentication endpoint of WSO2 Identity Server fails to provide a consistent system response when a username does not exist in the system, allowing attackers to differentiate between valid and invalid usernames. This difference in responses can be leveraged to enumerate existing user accounts. Successful exploitation enables an attacker to discover valid usernames within the system, significantly increasing the risk of subsequent attacks such as brute force attacks on user credentials, social engineering attacks, and information leakage. The discovered usernames can be used to craft targeted phishing emails or other social engineering campaigns.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7