CVE-2025-13591

MEDIUM
MEDIUM Priority: 0.02 BB Relevance: 71/100
Published: 2026-10-19 Modified: 2026-11-04 First seen: 2026-11-04 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
S: Unchanged
C: Low
I: None
A: None

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.

Weakness Classification (1)

Bug Bounty Relevance

71 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

CVSS Score

5.3 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS — Exploitation Probability

0.30%
Raw Score 0.002970
Percentile 22.7%
Date 2026-11-14

EPSS Trend

2026-11-14
0.00297
2026-11-13
0.00297
2026-11-12
0.00297
2026-11-10
0.00297
2026-11-09
0.00297
2026-11-08
0.00297
2026-11-07
0.00297
2026-11-06
0.00297
2026-11-05
0.00297
2026-11-04
0.00297

Intelligence Sources

nvd ref →