Using iterative requests an attacker was able to learn the size of an opaque response, as well as the contents of a server-supplied Vary header. This vulnerability affects Firefox < 119.

GLPI 9.5.7 contains a username enumeration vulnerability in the lost password recovery mechanism that allows attackers to validate email addresses. Attackers can systematically test email addresses by submitting requests to the password reset endpoint and analyzing response differences to identify valid user accounts.

Directus is a real-time API and App dashboard for managing SQL database content. Before 11.14.1, a timing-based user enumeration vulnerability exists in the password reset functionality. When an invalid reset_url parameter is provided, the response time differs by approximately 500ms between existing and non-existing users, enabling reliable user enumeration. This vulnerability is fixed in 11.14.1.

User enumeration vulnerability in /pwreset.php in osTicket v1.18.2 allows remote attackers to enumerate valid usernames registered in the platform.

In Talend Administration Center 7.3.1.20200219 before TAC-15950, the Forgot Password feature provides different error messages for invalid reset attempts depending on whether the email address is associated with any account. This allows remote attackers to enumerate accounts via a series of requests.

CVS 1.11.x before 1.11.17, and 1.12.x before 1.12.9, allows remote attackers to determine the existence of arbitrary files and directories via the -X command for an alternate history file, which causes different error messages to be returned.

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.

OpenSSH-portable (OpenSSH) 3.6.1p1 and earlier with PAM support enabled immediately sends an error message when a user does not exist, which allows remote attackers to determine valid usernames via a timing attack.

PF in OpenBSD 3.0 with the return-rst rule sets the TTL to 128 in the RST packet, which allows remote attackers to determine if a port is being filtered because the TTL is different than the default TTL.

IPFilter 3.4.25 and earlier sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.

PGP Security PGPfire 7.1 for Windows alters the system's TCP/IP stack and modifies packets in ICMP error messages in a way that allows remote attackers to determine that the system is running PGPfire.

One-Time Passwords In Everything (a.k.a OPIE) 2.32 and 2.4 allows remote attackers to determine the existence of user accounts by printing random passphrases if the user account does not exist and static passphrases if the user account does exist.

AmTote International homebet program returns different error messages when invalid account numbers and PIN codes are provided, which allows remote attackers to determine the existence of valid account numbers via a brute force attack.

A vulnerability has been identified in Mendix Forgot Password (Mendix 10 compatible) (All versions < V5.4.0), Mendix Forgot Password (Mendix 7 compatible) (All versions < V3.7.3), Mendix Forgot Password (Mendix 8 compatible) (All versions < V4.1.3), Mendix Forgot Password (Mendix 9 compatible) (All versions < V5.4.0). Applications using the affected module are 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.

An issue was discovered in OpenSlides before 4.2.5. During login at the /system/auth/login/ endpoint, the system's response times differ depending on whether a user exists in the system. The timing discrepancy stems from the omitted hashing of the password (e.g., more than 100 milliseconds).

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.

An issue was discovered in Aviatrix Controller before 5.4.1204. There is a Observable Response Discrepancy from the API, which makes it easier to perform user enumeration via brute force.

goauthentik is an open-source Identity Provider. In affected versions using a recovery flow with an identification stage an attacker is able to determine if a username exists. Only setups configured with a recovery flow are impacted by this. Anyone with a user account on a system with the recovery flow described above is susceptible to having their username/email revealed as existing. An attacker can easily enumerate and check users' existence using the recovery flow, as a clear message is shown when a user doesn't exist. Depending on configuration this can either be done by username, email, or both. This issue has been addressed in versions 2023.5.6 and 2023.6.2. Users are advised to upgrade. There are no known workarounds for this issue.

The commit 3730880 (April 2023) and v.0.9-beta1 of gugoan Economizzer has a user enumeration vulnerability in the login and forgot password functionalities. The app reacts differently when a user or email address is valid, and when it's not. This may allow an attacker to determine whether a user or email address is valid, or brute force valid usernames and email addresses.

CMAC verification functionality in Microchip Atmel ATSAMA5 products is vulnerable to vulnerable to timing and power analysis attacks.

An issue was discovered in eGroupWare 17.1.20190111. A User Enumeration vulnerability exists under calendar/freebusy.php, which allows unauthenticated remote attackers to enumerate the users of web applications based on server response.

IBM CICS TX Advanced 10.1 could disclose sensitive information to a remote attacker due to observable discrepancy in HTTP responses. IBM X-Force ID: 260814.

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.

An issue was discovered in the ProofreadPage (aka Proofread Page) extension for MediaWiki through 1.39.3. In includes/Page/PageContentHandler.php and includes/Page/PageDisplayHandler.php, hidden users can be exposed via public interfaces.

IBM Aspera Faspex 5.0.0 through 5.0.10 could disclose sensitive username information due to an observable response discrepancy.

The login functionality of the web server in affected devices does not normalize the response times of login attempts. An unauthenticated remote attacker could exploit this side-channel information to distinguish between valid and invalid usernames.

Adenza AxiomSL ControllerView through 10.8.1 is vulnerable to user enumeration. An attacker can identify valid usernames on the platform because a failed login attempt produces a different error message when the username is valid.

Tadiran Telecom Aeonix - CWE-204: Observable Response Discrepancy

A vulnerability has been identified in Desigo DXR2 (All versions < V01.21.142.5-22), Desigo PXC3 (All versions < V01.21.142.4-18), Desigo PXC4 (All versions < V02.20.142.10-10884), Desigo PXC5 (All versions < V02.20.142.10-10884). The login functionality of the application fails to normalize the response times of login attempts performed with wrong usernames with the ones executed with correct usernames. A remote unauthenticated attacker could exploit this side-channel information to perform a username enumeration attack and identify valid usernames.

Jenkins Configuration as Code Plugin 1.55 and earlier used a non-constant time comparison function when validating an authentication token allowing attackers to use statistical methods to obtain a valid authentication token.

A vulnerability in the External Interface of OTRS allows conclusions to be drawn about the existence of user accounts through different HTTP response codes and messages. This enables an attacker to systematically identify valid email addresses. This issue affects: * OTRS 7.0.X * OTRS 8.0.X * OTRS 2023.X * OTRS 2024.X * OTRS 2025.X

In NocoDB, versions 0.9 to 0.83.8 are vulnerable to Observable Discrepancy in the password-reset feature. When requesting a password reset for a given email address, the application displays an error message when the email isn't registered within the system. This allows attackers to enumerate the registered users' email addresses.

Observable Discrepancy in Packagist snipe/snipe-it prior to v5.3.9.

Flask-AppBuilder is an application development framework, built on top of the Flask web framework. In affected versions there exists a user enumeration vulnerability. This vulnerability allows for a non authenticated user to enumerate existing accounts by timing the response time from the server when you are logging in. Users are advised to upgrade to version 3.4.4 as soon as possible. There are no known workarounds for this issue.

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.

AMI BMC contains a vulnerability in the IPMI handler, where an unauthorized attacker can use certain oracles to guess a valid username, which may lead to information disclosure.

A vulnerability classified as problematic has been found in Rotem Dynamics Rotem CRM up to 20230729. This affects an unknown part of the file /LandingPages/api/otp/send?id=[ID][ampersand]method=sms of the component OTP URI Interface. The manipulation leads to information exposure through discrepancy. It is possible to initiate the attack remotely. The identifier VDB-233253 was assigned to this vulnerability. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.

A vulnerability in the TLS handler of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to gain access to sensitive information. This vulnerability is due to improper implementation of countermeasures against a Bleichenbacher attack on a device that uses SSL decryption policies. An attacker could exploit this vulnerability by sending crafted TLS messages to an affected device, which would act as an oracle and allow the attacker to carry out a chosen-ciphertext attack. A successful exploit could allow the attacker to perform cryptanalytic operations that may allow decryption of previously captured TLS sessions to the affected device.

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.

emoncms v11 and later was discovered to contain an information disclosure vulnerability which allows attackers to obtain the web directory path and other information leaked by the server via a crafted web request.

Allowing RTT frames to be linked with non randomized MAC address by comparing the sequence numbers can lead to information disclosure. in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer Electronics Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Voice & Music, Snapdragon Wired Infrastructure and Networking

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.

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, unauthenticated users can determine whether a specific user is a member of a private group by observing changes in directory results when using the `exclude_groups` parameter. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, disable public access to the user directory via Admin → Settings → hide user profiles from public.

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.

Avaya IX Workforce Engagement v15.2.7.1195 - User Enumeration - Observable Response Discrepancy

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.

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.

In BIG-IP 11.5.1-11.5.8 and 11.6.1-11.6.3, the Configuration Utility login page may not follow best security practices when handling a malicious request.