Weakness (CWE)
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.
How to prevent it (2 mitigations)
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Architecture and Design
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
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Implementation
Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success.
If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files.
Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.
Source: MITRE CWE-204
230 results · Feed
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Low 3.7
The login mechanism of Sage DPW 2021_06_004 displays distinct responses for valid and invalid usernames, allowing enume…
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Medium 4.7
The login mechanism of Sage DPW 2025_06_004 displays distinct responses for valid and invalid usernames, allowing enume…
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Medium 5.3
User enumeration in ESET Protect (on-prem)
User enumeration in ESET Protect (on-prem) via Response Timing.
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Critical 9.1
MinIO: LDAP login brute-force via user enumeration and missing rate limit
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) distin…
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Medium 6.3
Parse Server: Email verification resend page leaks user existence
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 respo…
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Medium 5.3
AVideo has Pre-Captcha User Enumeration and Account Status Disclosure in Password Recovery Endpoint
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…
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Medium 6.3
Chamilo LMS: User enumeration vulnerability via response
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.
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Medium 6.9
User enumeration in Raytha CMS
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.
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Medium 5.3
IBM Aspera Console Information Disclosure
IBM Aspera Console 3.3.0 through 3.4.8 could allow an attacker to enumerate usernames due to an observable response discrepancy.
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Medium 5.1
Username Enumeration Observable Response Discrepancy vulnerability has been discovered in OpenText™ Vertica.
Observable response discrepancy vulnerability in OpenText™ Vertica allows Password Brute Forcing. The vulnerability could lead to Password Brute Forcing in Vertica management console application.This issue affects Vertica: from 10.0 through 10.X, from 11.0 …
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Medium 6.3
Unauthenticated Host Enumeration via Observable Response Discrepancy on Deploy Agent Endpoint
Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows unauthenticated users to enumerate existing hosts by observing different HTTP response codes in deploy_agent endpoint, which could lead to…
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Medium 5.3
Authenticated Host Enumeration via Observable Response Discrepancy on Agent Register Existing Endpoint
Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows authenticated users to enumerate existing hosts by observing different HTTP response codes in agent-receiver/register_existing endpoint, w…
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Low 3.7
projectsend Auth.php response discrepancy
A flaw has been found in projectsend up to r1945. This impacts an unknown function of the file includes/Classes/Auth.php. Executing a manipulation of the argument ldap_email can lead to observable response discrepancy. The attack can be executed remotely. A h…
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Medium 6.3
Parse Server has user enumeration via email verification endpoint
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 ema…
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Medium 5.3
Shopware has user enumeration via distinct error codes on Store API login endpoint
Shopware is an open commerce platform. Prior to 6.7.8.1 and 6.6.10.15, the Store API login endpoint (POST /store-api/account/login) returns different error codes depending on whether the submitted email address belongs to a registered customer (CHECKOUT__CUST…
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Low 2.7CVE-2026-28358 Scanner template
NocoDB: User Enumeration via Password Reset Endpoint
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.
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Medium 5.5CVE-2026-28288 Scanner template
Dify has a user enumeration issue
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.
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Medium 5.3
Rucio WebUI has Username Enumeration via Login Error Message
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 depe…
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Medium 5.5CVE-2025-62512 Scanner template
Piwigo Vulnerable to User Enumeration via Password Reset Endpoint
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 …
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Medium 5.3
Static Web Server: Timing-Based Username Enumeration in Basic Authentication
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 exploitin…
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Medium 5.3CVE-2026-26744 Public exploit
A user enumeration vulnerability exists in FormaLMS 4.1.18 and below in the password recovery functionality accessible …
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Medium 5.3
Dokuwiki 2018-04-22b - Username Enumeration
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 exist…
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Medium 5.3
CI4MS Vulnerable to User Email Enumeration via Password Reset Flow
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 unauthen…
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Medium 5.3
Open eClass is Vulnerable to Username Enumeration via Login Response Discrepancies
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…
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Medium 4.3CVE-2026-24332 Public exploit
Discord through 2026-01-16 allows gathering information about whether a user's client state is Invisible (and not actua…
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Medium 5.3
ZITADEL has a user enumeration vulnerability in Login UIs
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 acco…
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Medium 5.3CVE-2026-21484 Scanner template
AnythingLLM Vulnerable to Username Enumeration w/ Password Recovery
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 …
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Medium 5.3
Gitea's /api/v1/user endpoint has different responses for failed authentication depending on whether a username exists
In Gitea before 1.25.2, /api/v1/user has different responses for failed authentication depending on whether a username exists.
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Medium 6.9
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 compromis…
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Medium 5.3
Pega Platform versions 7.1.0 through Infinity 25.1.0 are affected by a User Enumeration where during user authentication process, a difference in response time could allow a remote unauthenticated user to determine if a username is valid or not.
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…
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Low 3.7
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 give…
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Medium 6.9
IntelliChoice eFORCE Software Suite Username Enumeration
IntelliChoice eFORCE Software Suite 2.5.9 contains a username enumeration vulnerability that allows attackers to enumerate valid users by exploiting the 'ctl00$MainContent$UserName' POST parameter. Attackers can send requests with valid usernames to retrieve …
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Medium 5.3
A vulnerability has been identified in Gridscale X Prepay (All versions < V4.2.1). The affected application is vulnerab…
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Medium 5.3
Medtronic CareLink Network allows an unauthenticated remote attacker to initiate a request for security questions to an…
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Medium 5.3CVE-2025-65899 Public exploit
Kalmia CMS version 0.2.0 contains a user enumeration vulnerability in its authentication mechanism. The application ret…
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Medium 6.5
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" funct…
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Medium 6.9
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 con…
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Medium 5.3
Omnissa Workspace ONE UEM contains an observable response discrepancy vulnerability. A malicious actor may be able to e…
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Medium 5.3
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.
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Medium 6.9
Tibbo AggreGate Network Manager < 6.40.05 Login Functionality User Enumeration
Tibbo AggreGate Network Manager < 6.40.05 contains an observable response discrepancy in its login functionality. Authentication failure messages differ based on whether a supplied username exists or not, allowing an unauthenticated remote attacker to infer v…