CWE-204
Observable Response Discrepancy
The product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere.
userSpice 4.3.24 contains a username enumeration vulnerability that allows unauthenticated attackers to discover valid usernames by sending POST requests to the existingUsernameCheck.php endpoint. Attackers can submit usernames and analyze response text for the 'taken' string to identify existing accounts in the system.
In Eclipse Milo versions 0.6.0 through 1.1.4, username-token processing returns distinguishable errors for invalid RSA PKCS#1 v1.5 padding and other authentication failures, allowing an on-path attacker who captures a victim's `Basic128Rsa15`-encrypted username token to use repeated unauthenticated `ActivateSession` requests as a padding oracle, recover the victim's password, and authenticate with the recovered credentials.
Mojolicious versions from 4.59 before 9.48 for Perl expose a stable representation of the session CSRF token to a BREACH compression oracle. _csrf_token generates and caches one token per session and returns the same value on every call, and _csrf_field places that value in a hidden `csrf_token` input. When a response carrying the token also echoes attacker-controlled input and is gzip-compressed, the chosen values and the resulting compressed lengths form a BREACH oracle. An attacker able to query it can recover the token and pass csrf_protect validation.
MinIO is a high-performance object storage system. Prior to RELEASE.2026-03-17T21-25-16Z, MinIO AIStor's STS (Security Token Service) AssumeRoleWithLDAPIdentity endpoint is vulnerable to LDAP credential brute-forcing due to two combined weaknesses: (1) distinguishable error responses that enable username enumeration, and (2) absence of rate limiting on authentication attempts. An unauthenticated network attacker can enumerate valid LDAP usernames and then perform unlimited password guessing to obtain temporary AWS-style STS credentials, gaining access to the victim's S3 buckets and objects. This issue has been patched in RELEASE.2026-03-17T21-25-16Z.
User names used to access the web management interface are limited to the device identifier, which is a numerical identifier no more than 10 digits. A malicious actor can enumerate potential targets by incrementing or decrementing from known identifiers or through enumerating random digit sequences.
Observable response discrepancy in Azure Stack HCI allows an unauthorized attacker to disclose information over a network.
Combodo iTop is a web based IT service management tool. Prior to 3.2.3, iTop returns different responses for valid/invalid usernames depending on multiple factors in the reset password mechanism, leading to user enumeration. This issue has been fixed in version 3.2.3.
CWE-204: Observable Response Discrepancy
An unauthenticated remote attacker can enumerate valid user names from an unprotected endpoint.
A vulnerability in SonicWall SMA100 password change API allows a remote unauthenticated attacker to perform SMA100 username enumeration based on the server responses. This vulnerability impacts 10.2.1.2-24sv, 10.2.0.8-37sv and earlier 10.x versions.
In mymbCONNECT24, mbCONNECT24 <= 2.9.0 an unauthenticated user can enumerate valid backend users by checking what kind of response the server sends for crafted invalid login attempts.
An observable response discrepancy vulnerability in the SonicWall SMA1000 series appliances allows a remote attacker to enumerate SSL VPN user credentials.
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.
Automatisch reveals whether an address is registered through the response to its forgot-password request. The controller at packages/backend/src/controllers/internal/api/v1/users/forgot-password.js looks the address up and chains a not-found throw onto the query, so an address with no account raises an error that the global handler renders as a not-found status, while a registered address proceeds to send the reset message and returns no-content. The route is mounted without authentication. Submitting candidate addresses and comparing the two status codes therefore establishes which addresses hold accounts, with no credential and no rate limiting in the path.
Rocket.Chat exposes the sendForgotPasswordEmail Meteor method without a DDP rate limit, so an unauthenticated caller may invoke it as often as it likes. The method is reachable over DDP and over the HTTP route POST /api/v1/method.callAnon/sendForgotPasswordEmail, and it triggers a password reset message for any address that matches an account. With no DDPRateLimiter rule registered for it, a caller can drive an unbounded volume of reset mail at a chosen address from the deployment's own mail sender, and can probe addresses at scale: the method answers true for an address with no account and for a successful send, but false when the address belongs to an account that authenticates through an external provider and Accounts_AllowPasswordChangeForOAuthUsers is off, so repeated calls distinguish that class of account. Later versions register a rule permitting ten calls per minute per client address.
Frappe is a full-stack web application framework. Prior to 15.115.0 and 16.27.0, the public request-data web form and PersonalDataDownloadRequest class in frappe/website/doctype/personal_data_download_request/personal_data_download_request.py return distinguishable response shapes for registered and unregistered email addresses, including the user_name field and persistence behavior. A remote attacker can compare the responses to enumerate registered users. This issue is fixed in versions 15.115.0 and 16.27.0.
WPGraphQL provides a GraphQL API for WordPress sites. From 2.0.0 until 2.15.1, the deprecated user field on SendPasswordResetEmailPayload lets an unauthenticated caller distinguish existing author-class accounts through the sendPasswordResetEmail mutation and obtain public profile fields. This issue is fixed in version 2.15.1.
Rejetto HFS 3.0.0 through 3.2.0 returns observably different responses from its login endpoint depending on whether the submitted username exists. A remote unauthenticated attacker can use this to confirm valid account names, including the default admin account, facilitating password-guessing and session-forgery attacks.
MCO is vulnerable to User Enumeration through authentication-related functionalities. The application returns distinguishable responses for valid and invalid users during username reminder and password reset operations. An attacker can leverage these differences to enumerate valid usernames and email addresses. Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.
vantage6 is an open-source infrastructure for privacy preserving analysis. Versions prior to 5.0.0 provide an initial user with username `root` and password `root`. This is not ideal because attackers know that almost all vantage6 servers have a user with username `root` that probably has admin rights, and the initial password is very weak and it is possible that administrators forget to reset it. Version 5.0.0 fixes the issue. As a workaround, it is possible to delete the `root` user after it has been used to create other users.