FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains multiple TLS certificate identity validation weaknesses in tls_verify_certificate(), tls_match_hostname(), and x509_utils_get_dns_names(). Because FreeRDP performs custom Common Name and DNS SAN string matching instead of using OpenSSL's length-aware identity validation APIs, it (1) truncates DNS SAN values at embedded NUL bytes (accepting e.g. 'victim.example\0.attacker.example' as 'victim.example'), (2) accepts a matching Common Name even when non-matching DNS SAN entries are present, and (3) accepts IP-literal targets via DNS/CN matching without comparing iPAddress SANs. Under a trusted or misissued certificate chain, an attacker positioned to present such a certificate can bypass server identity verification, weakening TLS server authentication.

FreeRDP before 3.29.0 improperly validates the Extended Key Usage (EKU) purpose of the peer certificate during client-side server TLS authentication. In x509_utils_verify(), when server-purpose (X509_PURPOSE_SSL_SERVER) verification fails, the code falls back to client-purpose and any-purpose verification, so a trusted, hostname-matching certificate valid only for clientAuth can be accepted as the RDP server certificate. In environments relying on EKU separation between client and server certificates, this allows a clientAuth-only certificate issued by a trusted CA to bypass server certificate purpose validation.

FreeRDP before 3.29.0 (affected versions <= 3.28.0) does not validate CRLF and control characters in the server-controlled RDP redirection TargetNetAddress field. This value is copied into the client's ServerHostname and, when the client connects through an HTTP proxy, is written directly into the proxy CONNECT request line and Host header by http_proxy_connect() without filtering. A malicious or compromised RDP server can send a crafted redirection PDU containing embedded control characters to inject arbitrary headers/requests into the HTTP proxy CONNECT request.

FreeRDP before 3.29.0 contains a buffer over-disclosure vulnerability in the gateway WebSocket transport (libfreerdp/core/gateway/websocket.c). The client's Pong reply reuses a fixed 1024-byte response stream whose length is not sealed to the actual received Ping payload, so a malicious gateway/WebSocket peer sending a non-empty Ping control frame causes the client to reply with an overlong Pong that discloses bytes beyond the received payload (the peer receives the masking key and can unmask the reply). A zero-length Ping reaches an assertion and terminates the client (denial of service).

FreeRDP before 3.28.0 (affected 3.x through 3.27.1) contains a double-free vulnerability in freerdp_client_rdp_file_apply_to_settings() (client/common/file.c) when parsing the selectedmonitors field of a .rdp connection file. The MonitorIds array is allocated through the settings object, and a raw non-owning pointer to it is freed on the strtoul error path without clearing settings->MonitorIds, leaving it dangling; at teardown freerdp_settings_free() frees the same buffer again. An attacker who convinces a victim to open a crafted .rdp file with oversized monitor tokens can trigger a size-controlled double-free in any FreeRDP CLI client (xfreerdp/sdl-freerdp/wlfreerdp) in the default configuration.

FreeRDP before 3.28.0 (affected <=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfreerdp/crypto/crypto.c). The function writes the modular-exponentiation result into the caller's output buffer via BN_bn2bin() and only afterward checks output_length > out_length, so out-of-bounds bytes are written before the bounds check. On the server side, when a client selects RDP Standard Security, the encrypted client random is decrypted into a fixed 32-byte buffer. Because the server publishes its RSA public key, an unauthenticated attacker can forge a ciphertext whose decrypted value is up to the full modulus length (e.g. 256 bytes for RSA-2048), overflowing the 32-byte heap buffer by up to ~224 attacker-controlled bytes pre-authentication, resulting in denial of service.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, the gdi_surface_bits() function processes SURFACE_BITS_COMMAND messages sent by the RDP server. When the command is handled using NSCodec, the bmp.width and bmp.height values provided by the server are not properly validated against the actual desktop dimensions. A malicious RDP server can supply crafted bmp.width and bmp.height values that exceed the expected surface size. Because these values are used during bitmap decoding and memory operations without proper bounds checking, this can lead to a heap buffer overflow. Since the attacker can also control the associated pixel data transmitted by the server, the overflow may be exploitable to overwrite adjacent heap memory. This vulnerability is fixed in 3.24.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Versions prior to 3.25.0 have an off-by-one in the path traversal filter in `channels/drive/client/drive_file.c`. The `contains_dotdot()` function catches `../` and `..\` mid-path but misses `..` when it's the last component with no trailing separator. A rogue RDP server can read, list, or write files one directory above the client's shared folder through RDPDR requests. This requires the victim to connect with drive redirection enabled. Version 3.25.0 patches the issue.

An exploitable denial of service vulnerability exists within the reading of proprietary server certificates in FreeRDP 2.0.0-beta1+android11. A specially crafted challenge packet can cause the program termination leading to a denial of service condition. An attacker can compromise the server or use man in the middle to trigger this vulnerability.

Usage of specific command line parameter in MongoDB Tools which was originally intended to just skip hostname checks, may result in MongoDB skipping all certificate validation. This may result in accepting invalid certificates.This issue affects: MongoDB Inc. MongoDB Database Tools 3.6 versions later than 3.6.5; 3.6 versions prior to 3.6.21; 4.0 versions prior to 4.0.21; 4.2 versions prior to 4.2.11; 100 versions prior to 100.2.0. MongoDB Inc. Mongomirror 0 versions later than 0.6.0.

In Jenkins Delphix Plugin 3.0.1 through 3.1.0 (both inclusive) a global option for administrators to enable or disable SSL/TLS certificate validation for Data Control Tower (DCT) connections fails to take effect until Jenkins is restarted when switching from disabled validation to enabled validation.

Vasion Print (formerly PrinterLogic) Virtual Appliance Host versions prior to 22.0.1049 and Application versions prior to 20.0.2786 (VA and SaaS deployments) contain insecure defaults and code patterns that disable TLS/SSL certificate verification for communications to printers and internal microservices. In multiple places, the application sets libcurl/PHP transport options such that CURLOPT_SSL_VERIFYHOST and CURLOPT_SSL_VERIFYPEER are effectively disabled, and environment variables (for example API_*_VERIFYSSL=false) are used to turn off verification for gateway and microservice endpoints. As a result, the client accepts TLS connections without validating server certificates (and, in some cases, uses clear-text HTTP), permitting on-path attackers to perform man-in-the-middle (MitM) attacks. An attacker able to intercept network traffic between the product and printers or microservices can eavesdrop on and modify sensitive data (including print jobs, configuration, and authentication tokens), inject malicious payloads, or disrupt service. This vulnerability has been identified by the vendor as: V-2024-024 — Insecure Communication to Printers & Microservices.

Improper certificate validation in Windows Cryptographic Services allows an unauthorized attacker to bypass a security feature over a network.

MicroWorld eScan AV's update mechanism failed to ensure authenticity and integrity of updates: update packages were delivered and accepted without robust cryptographic verification. As a result, an on-path attacker could perform a man-in-the-middle (MitM) attack and substitute malicious update payloads for legitimate ones. The eScan AV client accepted these substituted packages and executed or loaded their components (including sideloaded DLLs and Java/installer payloads), enabling remote code execution on affected systems. MicroWorld eScan confirmed remediation of the update mechanism on 2023-07-31 but versioning details are unavailable. NOTE: MicroWorld eScan disputes the characterization in third-party reports, stating the issue relates to 2018–2019 and that controls were implemented then.

Botan is a C++ cryptography library. In 3.11.0, the function Certificate_Store::certificate_known had a misleading name; it would return true if any certificate in the store had a DN (and subject key identifier, if set) matching that of the argument. It did not check that the cert it found and the cert it was passed were actually the same certificate. In 3.11.0 an extension of path validation logic was made which assumed that certificate_known only returned true if the certificates were in fact identical. The impact is that if an end entity certificate is presented, and its DN (and subject key identifier, if set) match that of any trusted root, the end entity certificate is accepted immediately as if it itself were a trusted root. , This vulnerability is fixed in 3.11.1.

The vulnerability have been reported to affect earlier versions of Helpdesk. If exploited, this improper certificate validation vulnerability could allow an attacker to spoof a trusted entity by interfering in the communication path between the host and client. QNAP has already fixed the issue in Helpdesk 3.0.3 and later.

An Improper Certificate Validation vulnerability in the Schweitzer Engineering Laboratories Real-Time Automation Controller (SEL RTAC) Web Interface could allow a remote unauthenticated attacker to conduct a man-in-the-middle (MitM) attack. See SEL Service Bulletin dated 2022-11-15 for more details.

libldap in certain third-party OpenLDAP packages has a certificate-validation flaw when the third-party package is asserting RFC6125 support. It considers CN even when there is a non-matching subjectAltName (SAN). This is fixed in, for example, openldap-2.4.46-10.el8 in Red Hat Enterprise Linux.

A misconfiguration vulnerability exists in the urvpn_client functionality of Milesight UR32L v32.3.0.5. A specially-crafted man-in-the-middle attack can lead to increased privileges. An attacker can perform a man-in-the-middle attack to trigger this vulnerability.