---
id: CVE-2025-13166
title: >-
  The SMS OTP flow fails to adequately handle error messages, allowing an
  attacker to infer the existence of registered user accounts based on the
  responses received during the OTP initiation process.


  This weakness can be exploited by an …
summary: >-
  The SMS OTP flow fails to adequately handle error messages, allowing an
  attacker to infer the existence of registered user accounts based on the
  responses received during the OTP initiation process.


  This weakness can be exploited by an …
severity: low
cvss: 3.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'
cwe:
  - CWE-203
vendor: WSO2
product: WSO2 Identity Server
affected:
  - identity_server >= 7.1.0 < 7.1.0.40
  - identity_server >= 7.2.0 < 7.2.0.2
published: '2026-09-15'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T19:13:15.430'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-13166'
references:
  - url: >-
      https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2025-4353/
    label: ed10eef1-636d-4fbe-9993-6890dfa878f8
tags:
  - nvd
  - cve.org
epss: 0.00217
epssPercentile: 0.12448
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-15T12:43:12.334732Z'
ingestedAt: '2026-09-15T10:35:28.511Z'
---

## Overview

The SMS OTP flow fails to adequately handle error messages, allowing an attacker to infer the existence of registered user accounts based on the responses received during the OTP initiation process.

This weakness can be exploited by an attacker to discover valid usernames within the system. The impact is amplified for accounts that have not configured a mobile number, as the enumeration is specifically tied to this condition. The discovery of these usernames can facilitate subsequent brute force attacks, social engineering attempts, and information leakage, potentially leading to reputational damage, loss of customer trust, and regulatory non-compliance.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.