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.
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.
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.
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.
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.
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.
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.
User enumeration vulnerability in Password Recovery plugin 1.2 version for Roundcube, which could allow a remote attacker to create a test script against the password recovery function to enumerate all users in the database.
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.
A Observable Response Discrepancy vulnerability in spacewalk-java of SUSE Manager Server 4.1, SUSE Manager Server 4.2 allows remote attackers to discover valid usernames. This issue affects: SUSE Manager Server 4.1 spacewalk-java versions prior to 4.1.46-1. SUSE Manager Server 4.2 spacewalk-java versions prior to 4.2.37-1.
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.
All CODESYS Visualization versions before V4.2.0.0 generate a login dialog vulnerable to information exposure allowing a remote, unauthenticated attacker to enumerate valid users.
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.
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.
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.
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.
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.
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.
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.
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.
A remote, unauthenticated attacker can enumerate valid users by sending specific requests to the webservice of MB connect line mymbCONNECT24, mbCONNECT24 and Helmholz myREX24 and myREX24.virtual in all versions through v2.11.2.
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.
Zitadel is open-source identity infrastructure software. ZITADEL administrators can enable a setting called "Ignoring unknown usernames" which helps mitigate attacks that try to guess/enumerate usernames. If enabled, ZITADEL will show the password prompt even if the user doesn't exist and report "Username or Password invalid". While the setting was correctly respected during the login flow, the user's username was normalized leading to a disclosure of the user's existence. This vulnerability is fixed in 2.71.6, 2.70.8, 2.69.9, 2.68.9, 2.67.13, 2.66.16, 2.65.7, 2.64.6, and 2.63.9.
A vulnerability in Qlik Sense Enterprise on Windows could allow an remote attacker to enumerate domain user accounts. An attacker could exploit this vulnerability by sending authentication requests to an affected system. A successful exploit could allow the attacker to compare the response time that are returned by the affected system to determine which accounts are valid user accounts. Affected systems are only vulnerable if they have LDAP configured. The affected URI is /internal_forms_authentication/ the response time of the form is longer if the supplied user does not exists and shorter if the user 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.
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.
pimcore/admin-ui-classic-bundle provides a Backend UI for Pimcore. In affected versions an error message discloses existing accounts and leads to user enumeration on the target via "Forgot password" function. No generic error message has been implemented. This issue has been addressed in version 1.7.4 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
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.
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.
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.
IBM Security Verify Access Appliance and Docker 10.0 through 10.0.8 could allow a remote attacker to enumerate usernames due to an observable response discrepancy of disabled accounts.
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.
Observable Response Discrepancy in the SICK ICR890-4 could allow a remote attacker to identify valid usernames for the FTP server from the response given during a failed login attempt.
IBM Security QRadar EDR 3.12 could disclose sensitive information due to an observable login response discrepancy. IBM X-Force ID: 257697.