Nextcloud Server before 12.0.8 and 13.0.3 suffer from improper authentication on the OAuth2 token endpoint. Missing checks potentially allowed handing out new tokens in case the OAuth2 client was partly compromised.

Nextcloud Talk is a video and audio conferencing app for Nextcloud, a self-hosted productivity platform. Prior to versions 11.3.4, 12.2.2, and 13.0.0, when sharing a Deck card in conversation, the metaData can be manipulated so users can be tricked into opening arbitrary URLs. This issue is fixed in versions 11.3.4, 12.2.2, and 13.0.0. There are currently no known workarounds.

nextcloud news-android is an Android client for the Nextcloud news/feed reader app. In affected versions the Nextcloud News for Android app has a security issue by which a malicious application installed on the same device can send it an arbitrary Intent that gets reflected back, unintentionally giving read and write access to non-exported Content Providers in Nextcloud News for Android. Users should upgrade to version 0.9.9.63 or higher as soon as possible.

Nextcloud Android Client is the Android client for Nextcloud. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.16.1, the Nextcloud Android client skipped a step that involved the client checking if a private key belonged to a previously downloaded public certificate. If the Nextcloud instance served a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. The vulnerability is patched in version 3.16.1. As a workaround, do not add additional end-to-end encrypted devices to a user account.

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.3.0, the Nextcloud Desktop client fails to check if a private key belongs to previously downloaded public certificate. If the Nextcloud instance serves a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. This issue is fixed in Nextcloud Desktop Client version 3.3.0. There are no known workarounds aside from upgrading.

Nextcloud Desktop Client before 3.3.1 is vulnerable to improper certificate validation due to lack of SSL certificate verification when using the "Register with a Provider" flow.

Nextcloud also ships a CLI utility called nextcloudcmd which is sometimes used for automated scripting and headless servers. Versions of nextcloudcmd prior to 3.6.1 would incorrectly trust invalid TLS certificates, which may enable a Man-in-the-middle attack that exposes sensitive data or credentials to a network attacker. This affects the CLI only. It does not affect the standard GUI desktop Nextcloud clients, and it does not affect the Nextcloud server.

A missing verification of the TLS host in Nextcloud Mail 1.1.3 allowed a man in the middle attack.

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with your computer. The Desktop client did not stop with an error but allowed by-passing the signature validation, if a manipulated server sends an empty initial signature. It is recommended that the Nextcloud Desktop client is upgraded to 3.14.2 or later.

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server. Starting with version 3.0.0 and prior to version 3.7.0, by trusting that the server will return a certificate that belongs to the keypair of the user, a malicious server could get the desktop client to encrypt files with a key known to the attacker. This issue is fixed in Nextcloud Desktop 3.7.0. No known workarounds are available.

An Improper Certificate Validation weakness in the SRX Series Application Identification (app-id) signature update client of Juniper Networks Junos OS allows an attacker to perform Man-in-the-Middle (MitM) attacks which may compromise the integrity and confidentiality of the device. This issue affects: Juniper Networks Junos OS 15.1X49 versions prior to 15.1X49-D120 on SRX Series devices. No other versions of Junos OS are affected.

A vulnerability exists in the component RTU500 Scripting interface. When a client connects to a server using TLS, the server presents a certificate. This certificate links a public key to the identity of the service and is signed by a Certification Authority (CA), allowing the client to validate that the remote service can be trusted and is not malicious. If the client does not validate the parameters of the certificate, then attackers could be able to spoof the identity of the service. An attacker could exploit the vulnerability by using faking the identity of a RTU500 device and intercepting the messages initiated via the RTU500 Scripting interface.

Cerulean Studios Trillian 3.1 Basic does not check SSL certificates during MSN authentication, which allows remote attackers to obtain MSN credentials via a man-in-the-middle attack with a spoofed SSL certificate.

The int_x509_param_set_hosts function in lib/libcrypto/x509/x509_vpm.c in LibreSSL 2.7.0 before 2.7.1 does not support a certain special case of a zero name length, which causes silent omission of hostname verification, and consequently allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate. NOTE: the LibreSSL documentation indicates that this special case is supported, but the BoringSSL documentation does not.

The Certificate Trust Policy component in Apple Mac OS X before 10.6.8 does not perform CRL checking for Extended Validation (EV) certificates that lack OCSP URLs, which might allow man-in-the-middle attackers to spoof an SSL server via a revoked certificate.

A vulnerability exists in the FOXMAN-UN/UNEM server that affects the message queueing mechanism’s certificate validation. If exploited an attacker could spoof a trusted entity causing a loss of confidentiality and integrity.

lib/oauth/consumer.rb in the oauth-ruby gem through 0.5.4 for Ruby does not verify server X.509 certificates if a certificate bundle cannot be found, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information.

The PrinterLogic Print Management software, versions up to and including 18.3.1.96, does not validate, or incorrectly validates, the PrinterLogic management portal's SSL certificate. When a certificate is invalid or malicious, it might allow an attacker to spoof a trusted entity by using a man-in-the-middle (MITM) attack. The software might connect to a malicious host while believing it is a trusted host, or the software might be deceived into accepting spoofed data that appears to originate from a trusted host.

Improper Certificate Validation in GitHub repository pyload/pyload prior to 0.5.0b3.dev44.

A vulnerability has been identified in Siveillance VMS Video for Android (All versions < V12.1a (2018 R1)), Siveillance VMS Video for iOS (All versions < V12.1a (2018 R1)). Improper certificate validation could allow an attacker in a privileged network position to read data from and write data to the encrypted communication channel between the app and a server. The security vulnerability could be exploited by an attacker in a privileged network position which allows intercepting the communication channel between the affected app and a server (such as Man-in-the-Middle). Furthermore, an attacker must be able to generate a certificate that results for the validation algorithm in a checksum identical to a trusted certificate. Successful exploitation requires no user interaction. The vulnerability could allow reading data from and writing data to the encrypted communication channel between the app and a server, impacting the communication's confidentiality and integrity. At the time of advisory publication no public exploitation of this security vulnerability was known. Siemens confirms the security vulnerability and provides mitigations to resolve the security issue.

Due to improper validation of certificate in SAP Cloud Connector - version 2.0, attacker can impersonate the genuine servers to interact with SCC breaking the mutual authentication. Hence, the attacker can intercept the request to view/modify sensitive information. There is no impact on the availability of the system.

F5 Access for Android before version 3.1.2 which uses HTTPS does not verify the remote endpoint identity. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

A vulnerability has been discovered in Bitdefender Total Security HTTPS scanning functionality that results in the improper trust of self-signed certificates. The product is found to trust certificates signed with the RIPEMD-160 hashing algorithm without proper validation, allowing an attacker to establish MITM SSL connections to arbitrary sites.

A man in the middle vulnerability exists in Jenkins Inedo BuildMaster Plugin 1.3 and earlier in BuildMasterConfiguration.java, BuildMasterConfig.java, BuildMasterApi.java that allows attackers to impersonate any service that Jenkins connects to.

A vulnerability has been discovered in Bitdefender Total Security HTTPS scanning functionality that results in the improper trust of certificates issued using the DSA signature algorithm. The product does not properly check the certificate chain, allowing an attacker to establish MITM SSL connections to arbitrary sites using a DSA-signed certificate.

A vulnerability has been identified in Bitdefender Total Security HTTPS scanning functionality where the software fails to properly validate website certificates. Specifically, if a site certificate lacks the "Server Authentication" specification in the Extended Key Usage extension, the product does not verify the certificate's compliance with the site, deeming such certificates as valid. This flaw could allow an attacker to perform a Man-in-the-Middle (MITM) attack, intercepting and potentially altering communications between the user and the website.

An improper certificate validation issue in Smartcard authentication in GitLab EE affecting all versions from 11.6 prior to 16.4.4, 16.5 prior to 16.5.4, and 16.6 prior to 16.6.2 allows an attacker to authenticate as another user given their public key if they use Smartcard authentication. Smartcard authentication is an experimental feature and has to be manually enabled by an administrator.

Improper certificate validation in Zoom Workplace for Linux before version 6.4.13 may allow an unauthorized user to conduct an information disclosure via network access.

An improper certificate validation vulnerability [CWE-295] in FortiADC 7.4.0, 7.2.0 through 7.2.3, 7.1 all versions, 7.0 all versions, 6.2 all versions, 6.1 all versions and 6.0 all versions may allow a remote and unauthenticated attacker to perform a Man-in-the-Middle attack on the communication channel between the device and various remote servers such as private SDN connectors and FortiToken Cloud.

Acronis True Image prior to 2021 Update 4 for Windows, Acronis True Image prior to 2021 Update 5 for Mac, Acronis Agent prior to build 26653, Acronis Cyber Protect prior to build 27009 did not implement SSL certificate validation.

The Apache Qpid Proton-J transport includes an optional wrapper layer to perform TLS, enabled by use of the 'transport.ssl(...)' methods. Unless a verification mode was explicitly configured, client and server modes previously defaulted as documented to not verifying a peer certificate, with options to configure this explicitly or select a certificate verification mode with or without hostname verification being performed. The latter hostname verifying mode was not implemented in Apache Qpid Proton-J versions 0.3 to 0.29.0, with attempts to use it resulting in an exception. This left only the option to verify the certificate is trusted, leaving such a client vulnerable to Man In The Middle (MITM) attack. Uses of the Proton-J protocol engine which do not utilise the optional transport TLS wrapper are not impacted, e.g. usage within Qpid JMS. Uses of Proton-J utilising the optional transport TLS wrapper layer that wish to enable hostname verification must be upgraded to version 0.30.0 or later and utilise the VerifyMode#VERIFY_PEER_NAME configuration, which is now the default for client mode usage unless configured otherwise.

Dell Networking OS10 versions prior to 10.4.3.0 contain a vulnerability in the Phone Home feature which does not properly validate the server's certificate authority during TLS handshake. Use of an invalid or malicious certificate could potentially allow an attacker to spoof a trusted entity by using a man-in-the-middle (MITM) attack.

A vulnerability has been identified in Bitdefender Total Security HTTPS scanning functionality where the software trusts a certificate issued by an entity that isn't authorized to issue certificates. This occurs when the "Basic Constraints" extension in the certificate indicates that it is meant to be an "End Entity”. This flaw could allow an attacker to perform a Man-in-the-Middle (MITM) attack, intercepting and potentially altering communications between the user and the website.

Missing SSL certificate validation in localstack v2.3.2 allows attackers to eavesdrop on communications between the host and server via a man-in-the-middle attack.

IBM Security Guardium EcoSystem 10.5 does not validate, or incorrectly validates, a certificate.This weakness might allow an attacker to spoof a trusted entity by using a man-in-the-middle (MITM) attack. The software might connect to a malicious host while believing it is a trusted host, or the software might be deceived into accepting spoofed data that appears to originate from a trusted host. IBM X-Force ID: 141417.

A man in the middle vulnerability exists in Jenkins Inedo ProGet Plugin 0.8 and earlier in ProGetApi.java, ProGetConfig.java, ProGetConfiguration.java that allows attackers to impersonate any service that Jenkins connects to.

A man in the middle vulnerability exists in Jenkins TraceTronic ECU-TEST Plugin 2.3 and earlier in ATXPublisher.java, ATXValidator.java that allows attackers to impersonate any service that Jenkins connects to.

Missing SSL Certificate Validation issue exists in Pluck 4.7.15 in update_applet.php, which could lead to man-in-the-middle attacks.

A vulnerability has been identified in SINUMERIK Analyse MyCondition (All versions), SINUMERIK Analyze MyPerformance (All versions), SINUMERIK Analyze MyPerformance /OEE-Monitor (All versions), SINUMERIK Analyze MyPerformance /OEE-Tuning (All versions), SINUMERIK Integrate Client 02 (All versions >= V02.00.12 < 02.00.18), SINUMERIK Integrate Client 03 (All versions >= V03.00.12 < 03.00.18), SINUMERIK Integrate Client 04 (V04.00.02 and all versions >= V04.00.15 < 04.00.18), SINUMERIK Integrate for Production 4.1 (All versions < V4.1 SP10 HF3), SINUMERIK Integrate for Production 5.1 (V5.1), SINUMERIK Manage MyMachines (All versions), SINUMERIK Manage MyMachines /Remote (All versions), SINUMERIK Manage MyMachines /Spindel Monitor (All versions), SINUMERIK Manage MyPrograms (All versions), SINUMERIK Manage MyResources /Programs (All versions), SINUMERIK Manage MyResources /Tools (All versions), SINUMERIK Manage MyTools (All versions), SINUMERIK Operate V4.8 (All versions < V4.8 SP8), SINUMERIK Operate V4.93 (All versions < V4.93 HF7), SINUMERIK Operate V4.94 (All versions < V4.94 HF5), SINUMERIK Optimize MyProgramming /NX-Cam Editor (All versions). Due to an error in a third-party dependency the ssl flags used for setting up a TLS connection to a server are overwitten with wrong settings. This results in a missing validation of the server certificate and thus in a possible TLS MITM szenario.

In faye-websocket before version 0.11.0, there is a lack of certification validation in TLS handshakes. The `Faye::WebSocket::Client` class uses the `EM::Connection#start_tls` method in EventMachine to implement the TLS handshake whenever a `wss:` URL is used for the connection. This method does not implement certificate verification by default, meaning that it does not check that the server presents a valid and trusted TLS certificate for the expected hostname. That means that any `wss:` connection made using this library is vulnerable to a man-in-the-middle attack, since it does not confirm the identity of the server it is connected to. For further background information on this issue, please see the referenced GitHub Advisory. Upgrading `faye-websocket` to v0.11.0 is recommended.

The Motorola MBP853 firmware does not correctly validate server certificates. This allows for a Man in The Middle (MiTM) attack to take place between a Motorola MBP853 camera and the servers it communicates with. In one such instance, it was identified that the device was downloading what appeared to be a client certificate.

A vulnerability was found in the Hot Rod client. This security issue occurs as the Hot Rod client does not enable hostname validation when using TLS, possibly resulting in a man-in-the-middle (MITM) attack.

TLS hostname verification when using the Apache ActiveMQ Client before 5.15.6 was missing which could make the client vulnerable to a MITM attack between a Java application using the ActiveMQ client and the ActiveMQ server. This is now enabled by default.

Burp Suite Community Edition 1.7.32 and 1.7.33 fail to validate the server certificate in a couple of HTTPS requests which allows a man in the middle to modify or view traffic.

WP-CLI is the command-line interface for WordPress. An improper error handling in HTTPS requests management in WP-CLI version 0.12.0 and later allows remote attackers able to intercept the communication to remotely disable the certificate verification on WP-CLI side, gaining full control over the communication content, including the ability to impersonate update servers and push malicious updates towards WordPress instances controlled by the vulnerable WP-CLI agent, or push malicious updates toward WP-CLI itself. The vulnerability stems from the fact that the default behavior of `WP_CLI\Utils\http_request()` when encountering a TLS handshake error is to disable certificate validation and retry the same request. The default behavior has been changed with version 2.5.0 of WP-CLI and the `wp-cli/wp-cli` framework (via https://github.com/wp-cli/wp-cli/pull/5523) so that the `WP_CLI\Utils\http_request()` method accepts an `$insecure` option that is `false` by default and consequently that a TLS handshake failure is a hard error by default. This new default is a breaking change and ripples through to all consumers of `WP_CLI\Utils\http_request()`, including those in separate WP-CLI bundled or third-party packages. https://github.com/wp-cli/wp-cli/pull/5523 has also added an `--insecure` flag to the `cli update` command to counter this breaking change. There is no direct workaround for the default insecure behavior of `wp-cli/wp-cli` versions before 2.5.0. The workaround for dealing with the breaking change in the commands directly affected by the new secure default behavior is to add the `--insecure` flag to manually opt-in to the previous insecure behavior.

core/imap/MCIMAPSession.cpp in Canary Mail before 3.22 has Missing SSL Certificate Validation for IMAP in STARTTLS mode.

The LINE MUSIC for Android version 3.1.0 to versions prior to 3.6.5 does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

The iRemoconWiFi App for Android version 4.1.7 and earlier does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

The ANA App for iOS version 4.0.22 and earlier does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

A man in the middle vulnerability exists in Jenkins CollabNet Plugin 2.0.4 and earlier in CollabNetApp.java, CollabNetPlugin.java, CNFormFieldValidator.java that allows attackers to impersonate any service that Jenkins connects to.