CVE-2025-13166 Username Enumeration via SMS OTP Flow in WSO2 Identity Server Allows User Account Discovery
Attackers can enumerate valid usernames via SMS OTP error messages, facilitating brute force attacks and social engineering.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-13166?
CVE-2025-13166 is a low-severity vulnerability in WSO2 Identity Server, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-203
Which versions are affected by CVE-2025-13166?
How do I fix CVE-2025-13166?
No fix has been published for CVE-2025-13166 yet. Limit exposure of the affected software until one is available.
Is CVE-2025-13166 being exploited?
There is no known exploitation of CVE-2025-13166 in the wild and no public exploit code.
Sources
Also known as GHSA-xwj5-m236-f9hp.