Security Advisory WSO2-2019-0663

Published: July 01, 2020

Version: 2.0.0

Severity: Medium

CVSS Score: 5.3 (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)


  • WSO2 API Manager : 3.2.0 or earlier
  • WSO2 IS as Key Manager : 5.10.0 or earlier
  • WSO2 Identity Server : 5.10.0 or earlier


A potential User Enumeration vulnerability has been found in WSO2 products.


This vulnerability is reproducible only If the showAuthFailureReason parameter is set to true for the BasicAuthenticator. When the basic authenticator is used, if wrong user credentials are entered, an error code is sent in the response params which indicates that the user does not exist in the system.


By leveraging a User Enumeration attack, an attacker can identify valid users of the system and exploit further attacks.


If you are using an affected product version, it is highly recommended to migrate to the latest released version to receive security fixes.

Otherwise, you may apply the relevant fixes to the product based on the public fix(s):


If you are a WSO2 customer with a support subscription, use WSO2 Update Manager (WUM) updates in order to apply the fix.


  • 2020-09-24: API Manager 3.2.0 added to the affected product list.