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.

Observable Response Discrepancy in SICK FTMg AIR FLOW SENSOR with Partnumbers 1100214, 1100215, 1100216, 1120114, 1120116, 1122524, 1122526 allows a remote attacker to gain information about valid usernames by analyzing challenge responses from the server via the REST interface.

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

Raytha CMS is vulnerable to User Enumeration in password reset functionality. Difference in messages could allow an attacker to determine if the login is valid or not, enabling a brute force attack with valid logins. This issue was fixed in version 1.5.0.

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.

A vulnerability in the web-based management interface of Cisco ECE could allow an unauthenticated, remote attacker to perform a username enumeration attack against an affected device. This vulnerability is due to differences in authentication responses that are sent back from the application as part of an authentication attempt. An attacker could exploit this vulnerability by sending authentication requests to an affected device. A successful exploit could allow the attacker to confirm existing user accounts, which could be used in further attacks. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

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.

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.

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.

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.

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.

Pimcore is an open source data & experience management platform. In versions prior to 10.1.3, it is possible to enumerate usernames via the forgot password functionality. This issue is fixed in version 10.1.3. As a workaround, one may apply the available patch manually.

A vulnerability was found in nasirkhan Laravel Starter up to 11.8.0. It has been rated as problematic. Affected by this issue is some unknown functionality of the file /forgot-password of the component Password Reset Handler. The manipulation of the argument Email leads to observable response discrepancy. The attack may be launched remotely. The complexity of an attack is rather high. The exploitation is known to be difficult. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-268784. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.

IBM TXSeries for Multiplatforms 9.1 and 11.1 could allow an attacker to enumerate usernames due to an observable login attempt response discrepancy.

InHand Networks IR615 Router's Versions 2.3.0.r4724 and 2.3.0.r4870 authentication process response indicates and validates the existence of a username. This may allow an attacker to enumerate different user accounts.

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.

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.

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.

Under certain circumstances a CCURE Portal user could enumerate user accounts in CCURE 9000 version 2.90 and prior versions.

User Enumeration via Discrepancies in Error Messages in the Celk Sistemas Celk Saude v.3.1.252.1 password recovery functionality which allows a remote attacker to enumerate users through discrepancies in the responses.

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.

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.

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.

A vulnerability has been identified in Polarion V2310 (All versions), Polarion V2404 (All versions < V2404.2). The login implementation of the affected application contains an observable response discrepancy vulnerability when validating usernames. This could allow an unauthenticated remote attacker to distinguish between valid and invalid 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.

IBM Cognos Controller 10.4.1, 10.4.2, and 11.0.0 could allow a remote user to enumerate usernames due to differentiating error messages on existing usernames. IBM X-Force ID: 199181.

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.

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.

Loway - CWE-204: Observable Response Discrepancy

Statamic is a Laravel and Git powered content management system (CMS). Prior to 5.73.21 and 6.15.0, responses from the forgot password forms hinted at whether an account existed for a given email address. An unauthenticated attacker could use this to enumerate valid users, which can aid in follow-up credential-based attacks. This vulnerability is fixed in 5.73.21 and 6.15.0.

ChurchCRM is an open-source church management system. In versions prior to 7.2.0, the public API login endpoint (/api/public/user/login) returns distinguishable HTTP response codes based on whether a username exists: 404 for non-existent users and 401 for valid users with incorrect passwords. An unauthenticated attacker can exploit this difference to enumerate valid usernames, with no rate limiting or account lockout to impede the process. This issue has been fixed in version 7.2.0.

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.

WWBN AVideo is an open source video platform. In versions up to and including 26.0, the password recovery endpoint at `objects/userRecoverPass.php` performs user existence and account status checks before validating the captcha. This allows an unauthenticated attacker to enumerate valid usernames and determine whether accounts are active, inactive, or banned — at scale and without solving any captcha — by observing three distinct JSON error responses. Commit e42f54123b460fd1b2ee01f2ce3d4a386e88d157 contains a patch.

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.

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.

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.

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.

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.

Observable Response Discrepancy in GitHub repository answerdev/answer prior to 1.0.6.

A user enumeration vulnerability exists in the login functionality of Ghost Foundation Ghost 5.9.4. A specially-crafted HTTP request can lead to a disclosure of sensitive information. An attacker can send a series of HTTP requests to trigger this vulnerability.

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.

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.