Medium · CVSS 5.3CVE-2025-13591

Username Enumeration via Authentication Endpoint in WSO2 Identity Server Allows User Account DiscoveryCVE-2025-13591

Answer in brief

CVE-2025-13591 records a Medium severity (CVSS 5.3) vulnerability in Username Enumeration via Authentication Endpoint in WSO2 Identity Server Allows User Account Discovery. The current sources do not mark it as known exploited. The current feed maps WSO2/Email OTP Authenticator (generic), WSO2/WSO2 Carbon Abstract OTP Authenticator (generic), WSO2/WSO2 Identity Server (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 19, 2026Updated Oct 19, 2026Source checked Oct 19, 2026First seen by HOL Oct 19, 2026Material review Oct 19, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.3
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps WSO2/Email OTP Authenticator (generic), WSO2/WSO2 Carbon Abstract OTP Authenticator (generic), WSO2/WSO2 Identity Server (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
WSO2/Email OTP Authenticatorgeneric	>=1.0.18 <1.0.18.8 \|\| >=1.0.30 <1.0.30.5	1.0.18.8, 1.0.30.5
WSO2/WSO2 Carbon Abstract OTP Authenticatorgeneric	>=1.0.5 <1.0.5.3 \|\| >=1.0.10 <1.0.10.2	1.0.5.3, 1.0.10.2
WSO2/WSO2 Identity Servergeneric	>=7.0.0 <7.0.0.134 \|\| >=7.1.0 <7.1.0.42	7.0.0.134, 7.1.0.42

Recommended response

Check inventory. Check lockfiles and deployed manifests for WSO2/Email OTP Authenticator, WSO2/WSO2 Carbon Abstract OTP Authenticator, WSO2/WSO2 Identity Server.
Review the reported fix. Source-reported solution: Follow the instructions given on https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2025-4583/#solution

Evidence timeline and material changes

Published upstream
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 19, 2026

Sources and claim methodology

Source referencesecurity.docs.wso2.com

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.