CVE-2025-1396: wso2 identity_server Observable Discrepancy

Vulnerability summary

CVE-2025-1396 is a medium (CVSS 5.3) Observable Discrepancy vulnerability in wso2 identity_server. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.4% of scored vulnerabilities.

Timeline

1. 26-09-2025
   PublishedVulnerability first disclosed.
2. 30-09-2025
   Last modifiedVulnerability information updated.

Description

A username enumeration vulnerability exists in multiple WSO2 products when Multi-Attribute Login is enabled. In this configuration, the system returns a distinct "User does not exist" error message to the login form, regardless of the validate_username setting. This behavior allows malicious actors to determine which usernames exist in the system based on observable discrepancies in the application's responses. Exploitation of this vulnerability could aid in brute-force attacks, targeted phishing campaigns, or other social engineering techniques by confirming the validity of user identifiers within the system.

• CWE-203Observable DiscrepancyThe product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.