In CentOS-WebPanel.com (aka CWP) CentOS Web Panel 0.9.8.848, the Login process allows attackers to check whether a username is valid by comparing response times.

The NPSVG3.dll ActiveX control for Adobe SVG Viewer 3.02 and earlier, when running on Internet Explorer, allows remote attackers to determine the existence of arbitrary files by setting the src property to the target filename and using Javascript to determine if the web page immediately stops loading, which indicates whether the file exists or not.

Umbraco is a free and open source .NET content management system. Starting in version 14.0.0 and prior to versions 14.3.2 and 15.1.2, it's possible to determine whether an account exists based on an analysis of response codes and timing of Umbraco management API responses. Versions 14.3.2 and 15.1.2 contain a patch. No known workarounds are available.

webcalendar before 1.2.7 shows the reason for a failed login (e.g., "no such user").

In the Voatz application 2020-01-01 for Android, the amount of data transmitted during a single voter's vote depends on the different lengths of the metadata across the available voting choices, which makes it easier for remote attackers to discover this voter's choice by sniffing the network. For example, a small amount of sniffed data may indicate that a vote was cast for the candidate with the least metadata. An active man-in-the-middle attacker can leverage this behavior to disrupt voters' abilities to vote for a candidate opposed by the attacker.

Nettica Corporation INTELLIPEER Email Server 1.01 displays different error messages for valid and invalid account names, which allows remote attackers to determine valid account names.

ArGoSoft FTP before 1.4.2.1 generates an error message if the user name does not exist instead of prompting for a password, which allows remote attackers to determine valid usernames.

LabVantage LIMS 8.3 does not properly maintain the confidentiality of database names. For example, the web application exposes the database name. An attacker might be able to enumerate database names by providing his own database name in a request, because the response will return an 'Unrecognized Database exception message if the database does not exist.

YaBB 1 SP 1.3.1 displays different error messages when a user exists or not, which makes it easier for remote attackers to identify valid users and conduct a brute force password guessing attack.

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.

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.

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.

Novell iChain 2.2 before Support Pack 1 uses a shorter timeout for a non-existent user than a valid user, which makes it easier for remote attackers to guess usernames and conduct brute force password guessing.

The open-source identity infrastructure software Zitadel allows administrators to disable the user self-registration. Versions 4.0.0 to 4.0.2, 3.0.0 to 3.3.6, and all versions prior to 2.71.15 are vulnerable to a username enumeration issue in the login interface. The login UI includes a security feature, Ignoring unknown usernames, that is intended to prevent username enumeration by returning a generic response for both valid and invalid usernames. This vulnerability allows an unauthenticated attacker to bypass this protection by submitting arbitrary userIDs to the select account page and distinguishing between valid and invalid accounts based on the system's response. For effective exploitation, an attacker needs to iterate through possible userIDs, but the impact can be limited by implementing rate limiting or similar measures. The issue has been patched in versions 4.0.3, 3.4.0, and 2.71.15.

ssl3_get_record in s3_pkt.c for OpenSSL before 0.9.7a and 0.9.6 before 0.9.6i does not perform a MAC computation if an incorrect block cipher padding is used, which causes an information leak (timing discrepancy) that may make it easier to launch cryptographic attacks that rely on distinguishing between padding and MAC verification errors, possibly leading to extraction of the original plaintext, aka the "Vaudenay timing attack."

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.

Kanboard is project management software that focuses on the Kanban methodology. Prior to version 1.2.46, Kanboard is vulnerable to username enumeration and IP spoofing-based brute-force protection bypass. By analyzing login behavior and abusing trusted HTTP headers, an attacker can determine valid usernames and circumvent rate-limiting or blocking mechanisms. Any organization running a publicly accessible Kanboard instance is affected, especially if relying on IP-based protections like Fail2Ban or CAPTCHA for login rate-limiting. Attackers with access to the login page can exploit this flaw to enumerate valid usernames and bypass IP-based blocking mechanisms, putting all user accounts at higher risk of brute-force or credential stuffing attacks. Version 1.2.46 contains a patch for the issue.

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.

Versions before 8.9.1, Various resources in Jira responded with a 404 instead of redirecting unauthenticated users to the login page, in some situations this may have allowed unauthorised attackers to determine if certain resources exist or not through an Information Disclosure vulnerability.

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.

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.

An information leak in Nabu Casa Home Assistant Operating System and Home Assistant Supervised 2022.03 allows a DNS operator to gain knowledge about internal network resources via the hardcoded DNS resolver configuration.

A vulnerability in the TLS handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 1000 Series firewalls could allow an unauthenticated, remote attacker to gain access to sensitive information. The vulnerability is due to improper implementation of countermeasures against the Bleichenbacher attack for cipher suites that rely on RSA for key exchange. An attacker could exploit this vulnerability by sending crafted TLS messages to the 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. To exploit this vulnerability, an attacker must be able to perform both of the following actions: Capture TLS traffic that is in transit between clients and the affected device Actively establish a considerable number of TLS connections to the affected device

An issue was discovered in Arm Mbed TLS before 2.23.0. Because of a side channel in modular exponentiation, an RSA private key used in a secure enclave could be disclosed.

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.

An issue was discovered in Arm Mbed TLS before 2.23.0. A side channel allows recovery of an ECC private key, related to mbedtls_ecp_check_pub_priv, mbedtls_pk_parse_key, mbedtls_pk_parse_keyfile, mbedtls_ecp_mul, and mbedtls_ecp_mul_restartable.

The firewall in Astaro Security Linux before 4.024 sends responses to SYN-FIN packets, which makes it easier for remote attackers to obtain information about the system and construct specialized attacks.

An issue was discovered in MediaWiki before 1.35.1. Missing users (accounts that don't exist) and hidden users (accounts that have been explicitly hidden due to being abusive, or similar) that the viewer cannot see are handled differently, exposing sensitive information about the hidden status to unprivileged viewers. This exists on various code paths.

An issue was discovered in the SecurePoll extension for MediaWiki through 1.35.1. The non-admin vote list contains a full vote timestamp, which may provide unintended clues about how a voting process unfolded.

When binding against a DN during authentication, the reply from 389-ds-base will be different whether the DN exists or not. This can be used by an unauthenticated attacker to check the existence of an entry in the LDAP database.

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.

An issue was discovered in UTI Mutual fund Android application 5.4.18 and prior, allows attackers to brute force enumeration of usernames determined by the error message returned after invalid credentials are attempted.

An email address enumeration vulnerability exists in the password reset function of Rocket.Chat through 3.9.1.

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 Stop User Enumeration WordPress plugin before version 1.7.3 blocks REST API /wp-json/wp/v2/users/ requests for non-authorized users. However, this can be bypassed by URL-encoding the API path.

In Legion of the Bouncy Castle BC before 1.61 and BC-FJA before 1.0.1.2, attackers can obtain sensitive information about a private exponent because of Observable Differences in Behavior to Error Inputs. This occurs in org.bouncycastle.crypto.encodings.OAEPEncoding. Sending invalid ciphertext that decrypts to a short payload in the OAEP Decoder could result in the throwing of an early exception, potentially leaking some information about the private exponent of the RSA private key performing the encryption.

AIX 4.3.3 through AIX 5.1, when direct remote login is disabled, displays a different message if the password is correct, which allows remote attackers to guess the password via brute force methods.

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.

A vulnerability in Cisco Integrated Management Controller could allow an unauthenticated, remote attacker to enumerate valid usernames within the vulnerable application. The vulnerability is due to differences in authentication responses sent back from the application as part of an authentication attempt. An attacker could exploit this vulnerability by sending authentication requests to the affected application. A successful exploit could allow the attacker to confirm the names of administrative user accounts for use in further attacks.There are no workarounds that address this vulnerability.

Pritunl 1.29.2145.25 allows attackers to enumerate valid VPN usernames via a series of /auth/session login attempts. Initially, the server will return error 401. However, if the username is valid, then after 20 login attempts, the server will start responding with error 400. Invalid usernames will receive error 401 indefinitely. Note: This has been disputed by the vendor as not a vulnerability. They argue that this is an intended design

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.

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

The HCL Domino AppDev Pack IAM service is susceptible to a User Account Enumeration vulnerability.   During a failed login attempt a difference in messages could allow an attacker to determine if the user is valid or not.  The attacker could use this information to focus a brute force attack on 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).

Citrix ShareFile before 19.12 allows User Enumeration. It is possible to enumerate application username based on different server responses using the request to check the otp code. No authentication is required.

In BIG-IP 15.0.0, 14.1.0-14.1.0.6, 14.0.0-14.0.0.5, 13.0.0-13.1.1.5, 12.1.0-12.1.4.1, 11.5.1-11.6.4, BIG-IQ 7.0.0, 6.0.0-6.1.0,5.2.0-5.4.0, iWorkflow 2.3.0, and Enterprise Manager 3.1.1, the Configuration utility login page may not follow best security practices when handling a malicious request.

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.

Username enumeration is possible through Bypassing CAPTCHA in On-premise SureMDM Solution on Windows deployment allows attacker to enumerate local user information via error message. This issue affects SureMDM On-premise: 6.31 and below version

RSA BSAFE Crypto-C Micro Edition versions prior to 4.1.4 and RSA Micro Edition Suite versions prior to 4.4 are vulnerable to an Information Exposure Through Timing Discrepancy. A malicious remote user could potentially exploit this vulnerability to extract information leaving data at risk of exposure.

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.