Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.51 and 9.6.0-alpha.40, the Pages route and legacy PublicAPI route for resending email verification links return distinguishable responses depending on whether the provided username exists and has an unverified email. This allows an unauthenticated attacker to enumerate valid usernames by observing different redirect targets. The existing emailVerifySuccessOnInvalidEmail configuration option, which is enabled by default and protects the API route against this, did not apply to these routes. This issue has been patched in versions 8.6.51 and 9.6.0-alpha.40.

A vulnerability in an identity management API endpoint of Cisco ISE could allow an unauthenticated, remote attacker to enumerate valid user accounts on an affected device. This vulnerability exists because error messages are observed when the affected API endpoint is called. An attacker could exploit this vulnerability by sending a series of crafted requests to the affected endpoint and analyzing the differentiated responses. A successful exploit could allow the attacker to compile a list of valid usernames on an affected system.

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 8.6.34 and 9.6.0-alpha.8, the email verification endpoint (/verificationEmailRequest) returns distinct error responses depending on whether an email address belongs to an existing user, is already verified, or does not exist. An attacker can send requests with different email addresses and observe the error codes to determine which email addresses are registered in the application. This is a user enumeration vulnerability that affects any Parse Server deployment with email verification enabled (verifyUserEmails: true). This vulnerability is fixed in 8.6.34 and 9.6.0-alpha.8.

Chamilo LMS is a learning management system. Prior to version 1.11.36, Chamilo is vulnerable to user enumeration with valid/invalid username. This issue has been patched in version 1.11.36.

Dify is an open-source LLM app development platform. Prior to 1.9.0, responses from the Dify API to existing and non-existent accounts differ, allowing an attacker to enumerate email addresses registered with Dify. Version 1.9.0 fixes the issue.

NocoDB is software for building databases as spreadsheets. Prior to version 0.301.3, the password forgot endpoint returned different responses for registered and unregistered emails, allowing user enumeration. This issue has been patched in version 0.301.3.

Static Web Server (SWS) is a production-ready web server suitable for static web files or assets. In versions 2.1.0 through 2.40.1, a timing-based username enumeration vulnerability in Basic Authentication allows attackers to identify valid users by exploiting early responses for invalid usernames, enabling targeted brute-force or credential-stuffing attacks. SWS checks whether a username exists before verifying the password, causing valid usernames to follow a slower code path (e.g., bcrypt hashing) while invalid usernames receive an immediate 401 response. This timing discrepancy allows attackers to enumerate valid accounts by measuring response-time differences. This issue has been fixed in version 2.41.0.

Omnissa Workspace ONE UEM contains an observable response discrepancy vulnerability. A malicious actor may be able to enumerate sensitive information such as tenant ID and user accounts that could facilitate brute-force, password-spraying or credential-stuffing attacks.

CI4MS is a CodeIgniter 4-based CMS skeleton that delivers a production-ready, modular architecture with RBAC authorization and theme support. Prior to version 0.28.5.0, the authentication implementation in CI4MS is vulnerable to email enumeration. An unauthenticated attacker can determine whether an email address is registered in the system by analyzing the application's response during the password reset process. This issue has been patched in version 0.28.5.0.

The Open eClass platform (formerly known as GUnet eClass) is a complete course management system. Prior to version 4.2, a username enumeration vulnerability allows unauthenticated attackers to identify valid user accounts by analyzing differences in the login response behavior. This issue has been patched in version 4.2.

Rucio is a software framework that provides functionality to organize, manage, and access large volumes of scientific data using customizable policies. Prior to versions 35.8.3, 38.5.4, and 39.3.1, the WebUI login endpoint returns distinct error messages depending on whether a supplied username exists, allowing unauthenticated attackers to enumerate valid usernames. Versions 35.8.3, 38.5.4, and 39.3.1 fix the issue.

ZITADEL is an open source identity management platform. Prior to 4.9.1 and 3.4.6, a user enumeration vulnerability has been discovered in Zitadel's login interfaces. An unauthenticated attacker can exploit this flaw to confirm the existence of valid user accounts by iterating through usernames and userIDs. This vulnerability is fixed in 4.9.1 and 3.4.6.

AnythingLLM is an application that turns pieces of content into context that any LLM can use as references during chatting. Prior to commit e287fab56089cf8fcea9ba579a3ecdeca0daa313, the password recovery endpoint returns different error messages depending on whether a username exists, so enabling username enumeration. Commit e287fab56089cf8fcea9ba579a3ecdeca0daa313 fixes this issue.

The login mechanism of Sage DPW 2021_06_004 displays distinct responses for valid and invalid usernames, allowing enumeration of existing accounts in versions before 2021_06_000. On-premise administrators can toggle this behavior in newer versions.

DokuWiki 2018-04-22b contains a username enumeration vulnerability in its password reset functionality that allows attackers to identify valid user accounts. Attackers can submit different usernames to the password reset endpoint and distinguish between existing and non-existing accounts by analyzing the server's error response messages.

Pega Platform versions 7.1.0 through Infinity 25.1.0 are affected by a User Enumeration. This issue occurs during user authentication process, where a difference in response time could allow a remote unauthenticated user to determine if a username is valid or not. This only applies to deprecated basic-authentication feature and other more secure authentication mechanisms are recommended. A fix is being provided in the 24.1.4, 24.2.4, and 25.1.1 patch releases. Please note: Basic credentials authentication service type is deprecated started in 24.2 version: https://docs.pega.com/bundle/platform/page/platform/release-notes/security/whats-new-security-242.html.

Piwigo is an open source photo gallery application for the web. In version 15.5.0 and likely earlier 15.x releases, the password reset functionality in Piwigo allows an unauthenticated attacker to determine whether a given username or email address exists in the system. The endpoint at password.php?action=lost returns distinct messages for valid vs. invalid accounts, enabling user enumeration. As of time of publication, no known patches are available.

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.

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.

For failed login attempts, the application returns different error messages depending on whether the login failed due to an incorrect password or a non-existing username. This allows an attacker to guess usernames until they find an existing one.

Saleor is an e-commerce platform. Starting in version 3.21.0 and prior to version 3.21.16, requesting certain fields in the response of `accountRegister` may result in errors that could unintentionally reveal whether a user with the provided email already exists in Saleor. Version 3.21.16 fixes the issue. As a workaround, rate-limit the mutation to reduce the impact.

Loway - CWE-204: Observable Response Discrepancy

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.

Tuleap is an Open Source Suite created to facilitate management of software development and collaboration. In Tuleap Community Edition prior to version 16.9.99.1750843170 and Tuleap Enterprise Edition prior to 16.8-4 and 16.9-2, the forgot password form allows for user enumeration. This is fixed in Tuleap Community Edition version 16.9.99.1750843170 and Tuleap Enterprise Edition 16.8-4 and 16.9-2.

Cloud Native Computing Foundation Harbor before 1.10.3 and 2.x before 2.0.1 allows resource enumeration because unauthenticated API calls reveal (via the HTTP status code) whether a resource exists.

For failed login attempts, the application returns different error messages depending on whether the login failed due to an incorrect password or a non-existing username. This allows an attacker to guess usernames until they find an existing one.

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.

Observable Response Discrepancy vulnerability in Tridium Niagara Framework on Windows, Linux, QNX, Tridium Niagara Enterprise Security on Windows, Linux, QNX allows Cryptanalysis. This issue affects Niagara Framework: before 4.14.2, before 4.15.1, before 4.10.11; Niagara Enterprise Security: before 4.14.2, before 4.15.1, before 4.10.11.Tridium recommends upgrading to Niagara Framework and Enterprise Security versions 4.14.2u2, 4.15.u1, or 4.10u.11.

D-Link Nuclias Connect firmware versions <= 1.3.1.4 contain an observable response discrepancy vulnerability. The application's 'Login' endpoint returns distinct JSON responses depending on whether the supplied username is associated with an existing account. Because the responses differ in the `error.message`string value, an unauthenticated remote attacker can enumerate valid usernames/accounts on the server. NOTE: D-Link states that a fix is under development.

D-Link Nuclias Connect firmware versions <= 1.3.1.4 contain an observable response discrepancy vulnerability. The application's 'Forgot Password' endpoint returns distinct JSON responses depending on whether the supplied email address is associated with an existing account. Because the responses differ in the `data.exist` boolean value, an unauthenticated remote attacker can enumerate valid email addresses/accounts on the server. NOTE: D-Link states that a fix is under development.

web-auth/webauthn-lib is an open source set of PHP libraries and a Symfony bundle to allow developers to integrate that authentication mechanism into their web applications. The ProfileBasedRequestOptionsBuilder method returns allowedCredentials without any credentials if no username was found. When WebAuthn is used as the first or only authentication method, an attacker can enumerate usernames based on the absence of the `allowedCredentials` property in the assertion options response. This allows enumeration of valid or invalid usernames. By knowing which usernames are valid, attackers can focus their efforts on a smaller set of potential targets, increasing the efficiency and likelihood of successful attacks. This issue has been addressed in version 4.9.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

Matrix Tafnit v8 - CWE-204: Observable Response Discrepancy

Kaiten 57.128.8 allows remote attackers to enumerate user accounts via a crafted POST request, because a login response contains a user_email field only if the user account exists.

In Splunk Enterprise versions below 9.2.2, 9.1.5, and 9.0.10 and Splunk Cloud Platform versions below 9.1.2312.109, an attacker could determine whether or not another user exists on the instance by deciphering the error response that they would likely receive from the instance when they attempt to log in. This disclosure could then lead to additional brute-force password-guessing attacks. This vulnerability would require that the Splunk platform instance uses the Security Assertion Markup Language (SAML) authentication scheme.

An observable response discrepancy vulnerability [CWE-204] in FortiClientEMS 7.4.0, 7.2.0 through 7.2.4, 7.0 all versions, and FortiSOAR 7.5.0, 7.4.0 through 7.4.4, 7.3.0 through 7.3.2, 7.2 all versions, 7.0 all versions, 6.4 all versions may allow an unauthenticated attacker to enumerate valid users via observing login request responses.

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.

An issue was discovered in Logpoint before 7.4.0. An attacker can enumerate a valid list of usernames by observing the response time at the Forgot Password endpoint.

User enumeration vulnerability in ORDAT FOSS-Online before v2.24.01 allows attackers to determine if an account exists in the application by comparing the server responses of the forgot password functionality.

Umbraco is an ASP.NET content management system. Umbraco 10 prior to 10.8.4 with access to the native login screen is vulnerable to a possible user enumeration attack. This issue was fixed in version 10.8.5. As a workaround, one may disable the native login screen by exclusively using external logins.

OPEXUS FOIAXpress Public Access Link (PAL) version v11.1.0 allows an unauthenticated, remote attacker to query the /App/CreateRequest.aspx endpoint to check for the existence of valid usernames. There are no rate-limiting mechanisms in place.

Liferay Portal 7.2.0 through 7.4.1, and older unsupported versions, and Liferay DXP 7.3 before service pack 3, 7.2 before fix pack 18, and older unsupported versions returns with different responses depending on whether a site does not exist or if the user does not have permission to access the site, which allows remote attackers to discover the existence of sites by enumerating URLs. This vulnerability occurs if locale.prepend.friendly.url.style=2 and if a custom 404 page is used.

TN-5900 Series version 3.3 and prior versions is vulnearble to user enumeration vulnerability. The vulnerability may allow a remote attacker to determine whether a user is valid during password recovery through the web login page and enable a brute force attack with valid users.

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.

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.

The check user account lock states feature within the email OTP flow fails to validate user input, allowing an attacker to infer the existence of registered user accounts. The discovery of valid usernames can increase the risk of brute-force and social engineering attacks. Attackers can leverage this information to craft targeted phishing campaigns or other malicious activities aimed at tricking users into divulging sensitive data, potentially damaging the organization's reputation and leading to regulatory non-compliance and financial consequences.

A vulnerability has been identified in Mendix Runtime V10 (All versions < V10.21.0), Mendix Runtime V10.12 (All versions < V10.12.16), Mendix Runtime V10.18 (All versions < V10.18.5), Mendix Runtime V10.6 (All versions < V10.6.22), Mendix Runtime V8 (All versions < V8.18.35), Mendix Runtime V9 (All versions < V9.24.34). Affected applications allow for entity enumeration due to distinguishable responses in certain client actions. This could allow an unauthenticated remote attacker to list all valid entities and attribute names of a Mendix Runtime-based application.

A vulnerability has been identified in Mendix Runtime V10 (All versions < V10.17.0 only if the basic authentication mechanism is used by the application), Mendix Runtime V10.12 (All versions < V10.12.11 only if the basic authentication mechanism is used by the application), Mendix Runtime V10.6 (All versions < V10.6.19 only if the basic authentication mechanism is used by the application), Mendix Runtime V8 (All versions < V8.18.33 only if the basic authentication mechanism is used by the application), Mendix Runtime V9 (All versions < V9.24.31 only if the basic authentication mechanism is used by the application). The authentication mechanism of affected applications contains an observable response discrepancy vulnerability when validating usernames. This could allow unauthenticated remote attackers to distinguish between valid and invalid usernames.

Piccolo is an ORM and query builder which supports asyncio. In versions 0.120.0 and prior, the implementation of `BaseUser.login` leaks enough information to a malicious user such that they would be able to successfully generate a list of valid users on the platform. As Piccolo on its own does not also enforce strong passwords, these lists of valid accounts are likely to be used in a password spray attack with the outcome being attempted takeover of user accounts on the platform. The impact of this vulnerability is minor as it requires chaining with other attack vectors in order to gain more then simply a list of valid users on the underlying platform. The likelihood of this vulnerability is possible as it requires minimal skills to pull off, especially given the underlying login functionality for Piccolo based sites is open source. This issue has been patched in version 0.121.0.

User enumeration vulnerability in Arconte Áurea 1.5.0.0 version. The exploitation of this vulnerability could allow an attacker to obtain a list of registered users in the application, obtaining the necessary information to perform more complex attacks on the platform.

Silverware Games is a premium social network where people can play games online. Prior to version 1.3.6, the Password Recovery form would throw an error if the specified email was not found in our database. It would only display the "Enter the code" form if the email is associated with a member of the site. Since version 1.3.6, the "Enter the code" form is always returned, showing the message "If the entered email is associated with an account, a code will be sent now". This change prevents potential violators from determining if our site has a user with the specified email.