libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport, an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file, it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like `/tmp`), a malicious user can create a file name with the same name as the app wants to use by name, and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake.

In curl and libcurl 7.52.0 to and including 7.53.1, libcurl would attempt to resume a TLS session even if the client certificate had changed. That is unacceptable since a server by specification is allowed to skip the client certificate check on resume, and may instead use the old identity which was established by the previous certificate (or no certificate). libcurl supports by default the use of TLS session id/ticket to resume previous TLS sessions to speed up subsequent TLS handshakes. They are used when for any reason an existing TLS connection couldn't be kept alive to make the next handshake faster. This flaw is a regression and identical to CVE-2016-5419 reported on August 3rd 2016, but affecting a different version range.

When curl is told to use the Certificate Status Request TLS extension, often referred to as OCSP stapling, to verify that the server certificate is valid, it might fail to detect some OCSP problems and instead wrongly consider the response as fine. If the returned status reports another error than 'revoked' (like for example 'unauthorized') it is not treated as a bad certficate.

curl inadvertently kept the SSL session ID for connections in its cache even when the verify status (*OCSP stapling*) test failed. A subsequent transfer to the same hostname could then succeed if the session ID cache was still fresh, which then skipped the verify status check.

An improper certificate validation vulnerability exists in curl <v8.1.0 in the way it supports matching of wildcard patterns when listed as "Subject Alternative Name" in TLS server certificates. curl can be built to use its own name matching function for TLS rather than one provided by a TLS library. This private wildcard matching function would match IDN (International Domain Name) hosts incorrectly and could as a result accept patterns that otherwise should mismatch. IDN hostnames are converted to puny code before used for certificate checks. Puny coded names always start with `xn--` and should not be allowed to pattern match, but the wildcard check in curl could still check for `x*`, which would match even though the IDN name most likely contained nothing even resembling an `x`.

curl before 7.53.0 has an incorrect TLS Certificate Status Request extension feature that asks for a fresh proof of the server's certificate's validity in the code that checks for a test success or failure. It ends up always thinking there's valid proof, even when there is none or if the server doesn't support the TLS extension in question. This could lead to users not detecting when a server's certificate goes invalid or otherwise be mislead that the server is in a better shape than it is in reality. This flaw also exists in the command line tool (--cert-status).

libcurl would reuse a previously created connection even when a TLS or SSHrelated option had been changed that should have prohibited reuse.libcurl keeps previously used connections in a connection pool for subsequenttransfers to reuse if one of them matches the setup. However, several TLS andSSH settings were left out from the configuration match checks, making themmatch too easily.

The libcurl CURLOPT_SSL_VERIFYPEER option was disabled on a subset of requests made by Nest production devices which enabled a potential man-in-the-middle attack on requests to Google cloud services by any host the traffic was routed through.

libcurl skips the certificate verification for a QUIC connection under certain conditions, when built to use wolfSSL. If told to use an unknown/bad cipher or curve, the error path accidentally skips the verification and returns OK, thus ignoring any certificate problems.

curl 7.41.0 through 7.73.0 is vulnerable to an improper check for certificate revocation due to insufficient verification of the OCSP response.

The verify_certificate function in lib/vtls/schannel.c in libcurl 7.30.0 through 7.51.0, when built for Windows CE using the schannel TLS backend, makes it easier for remote attackers to conduct man-in-the-middle attacks via a crafted wildcard SAN in a server certificate, as demonstrated by "*.com."

The Toyoko Inn official App for iOS versions prior to 1.13.0 and Toyoko Inn official App for Android versions prior 1.3.14 don't properly verify server certificates, which allows a man-in-the-middle attacker to spoof servers and obtain sensitive information via a crafted certificate.

An improper certificate validation vulnerability [CWE-295] in FortiClientWindows 6.4 all versions, 7.0.0 through 7.0.7, FortiClientMac 6.4 all versions, 7.0 all versions, 7.2.0 through 7.2.4, FortiClientLinux 6.4 all versions, 7.0 all versions, 7.2.0 through 7.2.4, FortiClientAndroid 6.4 all versions, 7.0 all versions, 7.2.0 and FortiClientiOS 5.6 all versions, 6.0.0 through 6.0.1, 7.0.0 through 7.0.6 SAML SSO feature may allow an unauthenticated attacker to man-in-the-middle the communication between the FortiClient and  both the service provider and the identity provider.

Lack of TLS certificate verification in log transmission of a financial module within LINE Client for iOS prior to 13.16.0.

An improper certificate validation vulnerability [CWE-295] in FortiADC 7.4.0, 7.2 all versions, 7.1 all versions, 7.0 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 public SDN connectors.

An improper certificate validation vulnerability in Fortinet FortiOS 7.0.0 - 7.0.13, 7.2.0 - 7.2.6, 7.4.0 - 7.4.1 and 6.4 all versions allows a remote and unauthenticated attacker to perform a Man-in-the-Middle attack on the FortiLink communication channel between the FortiOS device and FortiSwitch.

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

Improper certificate validation in Ivanti Endpoint Manager before version 2024 SU1 or before version 2022 SU7 allows a remote unauthenticated attacker to intercept limited traffic between clients and servers.

ELECOM WRC-300FEBK-S contains an improper certificate validation vulnerability. Via a man-in-the-middle attack, an attacker may alter the communication response. As a result, an arbitrary OS command may be executed on the affected device.

A vulnerability in certification validation routines of Cisco ThousandEyes Endpoint Agent for macOS and RoomOS could allow an unauthenticated, remote attacker to intercept or manipulate metrics information. This vulnerability exists because the affected software does not properly validate certificates for hosted metrics services. An on-path attacker could exploit this vulnerability by intercepting network traffic using a crafted certificate. A successful exploit could allow the attacker to masquerade as a trusted host and monitor or change communications between the remote metrics service and the vulnerable client.

In BIG-IP Versions 15.1.x before 15.1.6.1, 14.1.x before 14.1.5, and all versions of 13.1.x, Traffic Intelligence feeds, which use HTTPS, do not verify the remote endpoint identity, allowing for potential data poisoning. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

'Hulu / フールー' App for iOS versions prior to 3.0.81 improperly verifies server certificates, which may allow an attacker to eavesdrop on an encrypted communication via a man-in-the-middle attack.

WeeChat (aka Wee Enhanced Environment for Chat) 3.2 to 3.4 before 3.4.1 does not properly verify the TLS certificate of the server, after certain GnuTLS options are changed, which allows man-in-the-middle attackers to spoof a TLS chat server via an arbitrary certificate. NOTE: this only affects situations where weechat.network.gnutls_ca_system or weechat.network.gnutls_ca_user is changed without a WeeChat restart.

An improper certificate validation vulnerability [CWE-295] in FortiNAC-F version 7.2.4 and below may allow a remote and unauthenticated attacker to perform a Man-in-the-Middle attack on the HTTPS communication channel between the FortiOS device, an inventory, and FortiNAC-F.

A vulnerability was found in HTC One/Sense 4.x. It has been rated as problematic. Affected by this issue is the certification validation of the mail client. An exploit has been disclosed to the public and may be used.

Jenkins Email Extension Plugin 2.75 and earlier does not perform hostname validation when connecting to the configured SMTP server.

An improper certificate validation vulnerability [CWE-295] in FortiOS 6.2 all versions, 6.4 all versions, 7.0.0 through 7.0.10, 7.2.0 and FortiProxy 1.2 all versions, 2.0 all versions, 7.0.0 through 7.0.9, 7.2.0 through 7.2.3 may allow a remote and unauthenticated attacker to perform a Man-in-the-Middle attack on the communication channel between the vulnerable device and the remote FortiGuard's map server.

Jiyu Kukan Toku-Toku coupon App for iOS versions 3.5.0 and earlier, and Jiyu Kukan Toku-Toku coupon App for Android versions 3.5.0 and earlier are vulnerable to improper server certificate verification. If this vulnerability is exploited, a man-in-the-middle attack may allow an attacker to eavesdrop on an encrypted communication.

IBM QRadar 7.3.0 to 7.3.3 Patch 2 does not validate, or incorrectly validates, a certificate which could allow an attacker to spoof a trusted entity by using a man-in-the-middle (MITM) attack. IBM X-ForceID: 170965.

Improper following of a certificate's chain of trust exists in SkyBridge MB-A200 firmware Ver. 01.00.05 and earlier, and SkyBridge BASIC MB-A130 firmware Ver. 1.4.1 and earlier, which may allow a remote unauthenticated attacker to eavesdrop on or alter the communication sent to the WebUI of the product.

In Splunk Add-on Builder (AoB) versions below 4.1.2 and the Splunk CloudConnect SDK versions below 3.1.3, requests to third-party APIs through the REST API Modular Input incorrectly revert to using HTTP to connect after a failure to connect over HTTPS occurs.

The AWV component of Mitel MiCollab before 9.3 could allow an attacker to perform a Man-In-the-Middle attack due to improper TLS negotiation. A successful exploit could allow an attacker to view and modify data.

An improper certificate validation vulnerability [CWE-295] in FortiPortal version 7.4.0, version 7.2.4 and below, version 7.0.8 and below, version 6.0.15 and below when connecting to a FortiManager device, a FortiAnalyzer device, or an SMTP server may allow an unauthenticated attacker in a Man-in-the-Middle position to intercept on and tamper with the encrypted communication channel established between the FortiPortal and those endpoints.

An improper certificate validation vulnerability [CWE-295] in FortiWeb 7.2.0 through 7.2.1, 7.0 all versions, 6.4 all versions and 6.3 all versions may allow a remote and unauthenticated attacker in a Man-in-the-Middle position to decipher and/or tamper with the communication channel between the device and different endpoints used to fetch data for Web Application Firewall (WAF).

TP-Link Tether versions prior to 4.5.13 and TP-Link Tapo versions prior to 3.3.6 do not properly validate certificates, which may allow a remote unauthenticated attacker to eavesdrop on an encrypted communication via a man-in-the-middle attack.

iSM client versions from V5.1 prior to V12.1 running on NEC Storage Manager or NEC Storage Manager Express does not verify a server certificate properly, which allows a man-in-the-middle attacker to eavesdrop on an encrypted communication or alter the communication via a crafted certificate.

An improper certificate validation vulnerability [CWE-295] in FortiOS 7.2.0 through 7.2.3, 7.0.0 through 7.0.7, 6.4 all versions, 6.2 all versions, 6.0 all versions and FortiProxy 7.0.0 through 7.0.6, 2.0 all versions, 1.2 all versions may allow a remote and unauthenticated attacker to perform a Man-in-the-Middle attack on the communication channel between the FortiOS/FortiProxy device and remote servers hosting threat feeds (when the latter are configured as Fabric connectors in FortiOS/FortiProxy)

Certain Liferay products are affected by: Missing SSL Certificate Validation in the Dynamic Data Mapping module's REST data providers. This affects Liferay Portal 7.1.0 through 7.4.2 and Liferay DXP 7.1 before fix pack 27, 7.2 before fix pack 17, and 7.3 before service pack 3.

HCL AppScan Source <= 10.6.0 does not properly validate a TLS/SSL certificate for an executable.

Jenkins Mailer Plugin 1.32 and earlier does not perform hostname validation when connecting to the configured SMTP server.