Mastodon Error Handling Discrepancy Enables Private Status Existence Enumeration

Mastodon is a free, open-source social network server based on ActivityPub. Versions 4.2.27 and prior, 4.3.0-beta.1 through 4.3.14, 4.4.0-beta.1 through 4.4.9, 4.5.0-beta.1 through 4.5.2 have discrepancies in error handling which allow checking whether a given status exists by sending a request with a non-English Accept-Language header. Using this behavior, an attacker who knows the identifier of a particular status they are not allowed to see can confirm whether this status exists or not. This cannot be used to learn the contents of the status or any other property besides its existence. This issue is fixed in versions 4.2.28, 4.3.15, 4.4.10 and 4.5.3.

Gitea: Gitea: Information disclosure via differing authentication responses

In Gitea before 1.25.2, /api/v1/user has different responses for failed authentication depending on whether a username exists.

A vulnerability has been identified in Gridscale X Prepay (All versions < V4.2.1). The affected application is vulnerable to user enumeration due to distinguishable responses. This could allow an unauthenticated remote attacker to determine if a user is valid or not, enabling a brute force attack with valid users.

Frontier Airlines publicly available email address validation

The Frontier Airlines website has a publicly available endpoint that validates if an email addresses is associated with an account. An unauthenticated, remote attacker could determine valid email addresses, possibly aiding in further attacks.

Medtronic CareLink Network allows an unauthenticated remote attacker to initiate a request for security questions to an API endpoint that could be used to determine a valid user account. This issue affects CareLink Network: before December 4, 2025.

ChurchCRM has plaintext password return in response

ChurchCRM is an open-source church management system. Prior to version 6.5.0, the application echoes back plaintext passwords submitted by users in subsequent HTTP responses. This information disclosure significantly increases the risk of credential compromise and may amplify the impact of other vulnerabilities (e.g., XSS, IDOR, session fixation), enabling attackers to harvest other users’ passwords. Version 6.5.0 fixes the issue.

Icinga DB Web hidden/protected custom variables are prone to filter enumeration

Icinga DB Web provides a graphical interface for Icinga monitoring. Before 1.1.4 and 1.2.3, an authorized user with access to Icinga DB Web, can use a custom variable in a filter that is either protected by icingadb/protect/variables or hidden by icingadb/denylist/variables, to guess values assigned to it. Versions 1.1.4 and 1.2.3 respond with an error if such a custom variable is used.

Kalmia CMS version 0.2.0 contains a user enumeration vulnerability in its authentication mechanism. The application returns different error messages for invalid users (user_not_found) versus valid users with incorrect passwords (invalid_password). This observable response discrepancy allows unauthenticated attackers to enumerate valid usernames on the system.

User enumeration in Windu CMS

Windu CMS is vulnerable to User Enumeration. This issue occurs during logon, where a difference in messages could allow an attacker to determine if the login is valid or not, enabling a brute force attack with valid logins. Only version 4.1 was tested and confirmed as vulnerable. This issue was fixed in version 4.1 build 2250.

Grav Admin Plugin vulnerable to User Enumeration & Email Disclosure

This admin plugin for Grav is an HTML user interface that provides a convenient way to configure Grav and easily create and modify pages. Prior to 1.11.0-beta.1, a user enumeration and email disclosure vulnerability exists in Grav. The "Forgot Password" functionality at /admin/forgot leaks information about valid usernames and their associated email addresses through distinct server responses. This allows an attacker to enumerate users and disclose sensitive email addresses, which can be leveraged for targeted attacks such as password spraying, phishing, or social engineering. This vulnerability is fixed in 1.11.0-beta.1.

Icinga 2 API users could access restricted values in filter expressions

Icinga 2 is an open source monitoring system. In Icinga 2 versions 2.4 through 2.15.0, filter expressions provided to the various /v1/objects endpoints could access variables or objects that would otherwise be inaccessible for the user. This allows authenticated API users to learn information that should be hidden from them, including global variables not permitted by the variables permission and objects not permitted by the corresponding objects/query permissions. The vulnerability is fixed in versions 2.15.1, 2.14.7, and 2.13.13.

Trivision NC-227WF firmware 5.80 (build 20141010) login mechanism reveals whether a username exists or not by returning different error messages ("Unknown user" vs. "Wrong password"), allowing an attacker to enumerate valid usernames.

IBM Control Center information disclosure

IBM Control Center 6.2.1 and 6.3.1 could allow a remote attacker to enumerate usernames due to an observable discrepancy between login attempts.

A CWE-204 "Observable Response Discrepancy" in the login page in Q-Free MaxTime less than or equal to version 2.11.0 allows an unauthenticated remote attacker to enumerate valid usernames via crafted HTTP requests.

Information Disclosure vulnerability in SAP NetWeaver Application Server ABAP

SAP NetWeaver Server ABAP allows an unauthenticated attacker to exploit a vulnerability that causes the server to respond differently based on the existence of a specified user, potentially revealing sensitive information. This issue does not enable data modification and has no impact on server availability.

Observable Response Discrepancy at Alma Devklan Blog

User enumeration vulnerability in Devklan's Alma Blog that affects versions 2.1.10 and earlier. This vulnerability could allow a remote user to retrieve all valid users registered in the application just by looking at the request response.

langhsu Mblog Blog System login observable response discrepancy

A vulnerability classified as problematic has been found in langhsu Mblog Blog System 3.5.0. Affected is an unknown function of the file /login. The manipulation leads to observable response discrepancy. It is possible to launch the attack remotely. The complexity of an attack is rather high. The exploitability is told to be difficult. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Shopware 6 allows attackers to check for registered accounts through the store-api

Shopware 6 is an open commerce platform based on Symfony Framework and Vue. Through the store-api it is possible as a attacker to check if a specific e-mail address has an account in the shop. Using the store-api endpoint /store-api/account/recovery-password you get the response, which indicates clearly that there is no account for this customer. In contrast you get a success response if the account was found. This vulnerability is fixed in Shopware 6.6.10.3 or 6.5.8.17. For older versions of 6.4, corresponding security measures are also available via a plugin. For the full range of functions, we recommend updating to the latest Shopware version.

Portabilis i-Diario Password Recovery Endpoint email observable response discrepancy

A security flaw has been discovered in Portabilis i-Diario up to 1.5.0. Affected by this vulnerability is an unknown functionality of the file /password/email of the component Password Recovery Endpoint. The manipulation results in observable response discrepancy. It is possible to launch the attack remotely. This attack is characterized by high complexity. The exploitation appears to be difficult. The exploit has been released to the public and may be exploited.

Umbraco Makes User Enumeration Feasible Based on Timing of Login Response

Umbraco is a free and open source .NET content management system. Prior to versions 10.8.10 and 13.8.1, based on an analysis of the timing of post login API responses, it's possible to determine whether an account exists. The issue is patched in versions 10.8.10 and 13.8.1. No known workarounds are available.