The X509_V_FLAG_X509_STRICT flag enables additional security checks of the certificates present in a certificate chain. It is not set by default. Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an additional strict check. An error in the implementation of this check meant that the result of a previous check to confirm that certificates in the chain are valid CA certificates was overwritten. This effectively bypasses the check that non-CA certificates must not be able to issue other certificates. If a "purpose" has been configured then there is a subsequent opportunity for checks that the certificate is a valid CA. All of the named "purpose" values implemented in libcrypto perform this check. Therefore, where a purpose is set the certificate chain will still be rejected even when the strict flag has been used. A purpose is set by default in libssl client and server certificate verification routines, but it can be overridden or removed by an application. In order to be affected, an application must explicitly set the X509_V_FLAG_X509_STRICT verification flag and either not set a purpose for the certificate verification or, in the case of TLS client or server applications, override the default purpose. OpenSSL versions 1.1.1h and newer are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1h-1.1.1j).

An issue pertaining to CWE-295: Improper Certificate Validation was discovered in YMFE yapi v1.12.0. The application disables TLS/SSL certificate validation by setting 'rejectUnauthorized': false in the HTTPS agent configuration for Axios requests

An issue pertaining to CWE-295: Improper Certificate Validation was discovered in jxcore jxm master. The application disables TLS/SSL certificate validation by setting 'rejectUnauthorized': false in HTTPS request options when 'jx_obj.IsSecure' is true

HashiCorp Consul and Consul Enterprise 1.3.0 through 1.10.0 Envoy proxy TLS configuration does not validate destination service identity in the encoded subject alternative name. Fixed in 1.8.14, 1.9.8, and 1.10.1.

Nim is a statically typed compiled systems programming language. In Nim standard library before 1.4.2, httpClient SSL/TLS certificate verification was disabled by default. Users can upgrade to version 1.4.2 to receive a patch or, as a workaround, set "verifyMode = CVerifyPeer" as documented.

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.

HashiCorp Vault and Vault Enterprise 1.5.1 and newer, under certain circumstances, may exclude revoked but unexpired certificates from the CRL. Fixed in 1.5.8, 1.6.4, and 1.7.1.

HashiCorp Vault and Vault Enterprise Cassandra integrations (storage backend and database secrets engine plugin) did not validate TLS certificates when connecting to Cassandra clusters. Fixed in 1.6.4 and 1.7.1

Aqara Hub devices including Camera Hub G3 4.1.9_0027, Hub M2 4.3.6_0027, and Hub M3 4.3.6_0025 fail to validate server certificates during HTTPS firmware downloads, allowing man-in-the-middle attackers to intercept firmware update traffic and potentially serve modified firmware files.

Aqara Hub devices including Hub M2 4.3.6_0027, Hub M3 4.3.6_0025, Camera Hub G3 4.1.9_0027 fail to validate server certificates in TLS connections for discovery services and CoAP gateway communications, enabling man-in-the-middle attacks on device control and monitoring.

The Proofpoint Insider Threat Management Agents (formerly ObserveIT Agent) for MacOS and Linux perform improper validation of the ITM Server's certificate, which enables a remote attacker to intercept and alter these communications using a man-in-the-middle attack. All versions before 7.11.1 are affected. Agents for Windows and Cloud are not affected.

Mifos-Mobile Android Application for MifosX is an Android Application built on top of the MifosX Self-Service platform. Mifos-Mobile before commit e505f62 disables HTTPS hostname verification of its HTTP client. Additionally it accepted any self-signed certificate as valid. Hostname verification is an important part when using HTTPS to ensure that the presented certificate is valid for the host. Disabling it can allow for man-in-the-middle attacks. Accepting any certificate, even self-signed ones allows man-in-the-middle attacks. This problem is fixed in mifos-mobile commit e505f62.

Dell EMC Unisphere for PowerMax versions before 9.1.0.27, Dell EMC Unisphere for PowerMax Virtual Appliance versions before 9.1.0.27, and PowerMax OS Release 5978 contain an improper certificate validation vulnerability. An unauthenticated remote attacker may potentially exploit this vulnerability to carry out a man-in-the-middle attack by supplying a crafted certificate and intercepting the victim's traffic to view or modify a victim’s data in transit.

The SNKRDUNK Market Place App for iOS versions prior to 2.2.0 does not verify server certificate properly, which allows man-in-the-middle attackers to eavesdrop on and/or alter encrypted communication via a crafted certificate.

OpenSearch Data Prepper as an open source data collector for observability data. In versions prior to 2.12.2, the OpenSearch sink and source plugins in Data Prepper trust all SSL certificates by default when no certificate path is provided. Prior to this fix, the OpenSearch sink and source plugins would automatically use a trust all SSL strategy when connecting to OpenSearch clusters if no certificate path was explicitly configured. This behavior bypasses SSL certificate validation, potentially allowing attackers to intercept and modify data in transit through man-in-the-middle attacks. The vulnerability affects connections to OpenSearch when the cert parameter is not explicitly provided. This issue has been patched in version 2.12.2. As a workaround, users can add the cert parameter to their OpenSearch sink or source configuration with the path to the cluster's CA certificate.

Multiple vulnerabilities in Cisco Data Center Network Manager (DCNM) could allow an attacker to spoof a trusted host or construct a man-in-the-middle attack to extract sensitive information or alter certain API requests. These vulnerabilities are due to insufficient certificate validation when establishing HTTPS requests with the affected device. For more information about these vulnerabilities, see the Details section of this advisory.

A vulnerability in the Cisco Advanced Malware Protection (AMP) for Endpoints integration of Cisco AsyncOS for Cisco Email Security Appliance (ESA) and Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to intercept traffic between an affected device and the AMP servers. This vulnerability is due to improper certificate validation when an affected device establishes TLS connections. A man-in-the-middle attacker could exploit this vulnerability by sending a crafted TLS packet to an affected device. A successful exploit could allow the attacker to spoof a trusted host and then extract sensitive information or alter certain API requests.

Multiple vulnerabilities in Cisco Data Center Network Manager (DCNM) could allow an attacker to spoof a trusted host or construct a man-in-the-middle attack to extract sensitive information or alter certain API requests. These vulnerabilities are due to insufficient certificate validation when establishing HTTPS requests with the affected device. For more information about these vulnerabilities, see the Details section of this advisory.

A vulnerability in the Cisco Identity Services Engine (ISE) integration feature of the Cisco DNA Center Software could allow an unauthenticated, remote attacker to gain unauthorized access to sensitive data. The vulnerability is due to an incomplete validation of the X.509 certificate used when establishing a connection between DNA Center and an ISE server. An attacker could exploit this vulnerability by supplying a crafted certificate and could then intercept communications between the ISE and DNA Center. A successful exploit could allow the attacker to view and alter sensitive information that the ISE maintains about clients that are connected to the network.

Dragonfly is an open source P2P-based file distribution and image acceleration system. Prior to 2.1.0, a peer can obtain a valid TLS certificate for arbitrary IP addresses, effectively rendering the mTLS authentication useless. The issue is that the Manager’s Certificate gRPC service does not validate if the requested IP addresses “belong to” the peer requesting the certificate—that is, if the peer connects from the same IP address as the one provided in the certificate request. This vulnerability is fixed in 2.1.0.

Avast AntiTrack before 1.5.1.172 and AVG Antitrack before 2.0.0.178 proxies traffic to HTTPS sites but does not validate certificates, and thus a man-in-the-middle can host a malicious website using a self-signed certificate. No special action necessary by the victim using AntiTrack with "Allow filtering of HTTPS traffic for tracking detection" enabled. (This is the default configuration.)

configurationwatcher.go in Traefik 2.x before 2.1.4 and TraefikEE 2.0.0 mishandles the purging of certificate contents from providers before logging.

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.

Missing validation of server certificates for out-going connections in Nextcloud Social < 0.4.0 allowed a man-in-the-middle attack.

In JetBrains IntelliJ IDEA before 2019.3, some Maven repositories were accessed via HTTP instead of HTTPS.

TLS session reuse can lead to host certificate verification bypass in node version < 12.18.0 and < 14.4.0.

Improper certificate validation for certain connections in the Bosch Smart Home System App for iOS prior to version 9.17.1 potentially allows to intercept video contents by performing a man-in-the-middle attack.

In versions of NGINX Controller prior to 3.2.0, communication between NGINX Controller and NGINX Plus instances skip TLS verification by default.

Android App 'MyPallete' and some of the Android banking applications based on 'MyPallete' do not verify X.509 certificates from servers, and also do not properly validate certificates with host-mismatch, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

The kantan netprint App for iOS 2.0.2 and earlier does not verify X.509 certificates from servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

In versions 15.0.0-15.1.0.1, 14.1.0-14.1.2.3, 13.1.0-13.1.3.4, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.2, the BIG-IP Client or Server SSL profile ignores revoked certificates, even when a valid CRL is present. This impacts SSL/TLS connections and may result in a man-in-the-middle attack on the connections.

The netprint App for iOS 3.2.3 and earlier does not verify X.509 certificates from servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

The kantan netprint App for Android 2.0.3 and earlier does not verify X.509 certificates from servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

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.

In SaltStack Salt before 3002.5, when authenticating to services using certain modules, the SSL certificate is not always validated.

An issue was discovered in Mbed TLS before 2.25.0 (and before 2.16.9 LTS and before 2.7.18 LTS). A NULL algorithm parameters entry looks identical to an array of REAL (size zero) and thus the certificate is considered valid. However, if the parameters do not match in any way, then the certificate should be considered invalid.

A vulnerability in the SSL implementation of the Cisco Intelligent Proximity solution could allow an unauthenticated, remote attacker to view or alter information shared on Cisco Webex video devices and Cisco collaboration endpoints if the products meet the conditions described in the Vulnerable Products section. The vulnerability is due to a lack of validation of the SSL server certificate received when establishing a connection to a Cisco Webex video device or a Cisco collaboration endpoint. An attacker could exploit this vulnerability by using man in the middle (MITM) techniques to intercept the traffic between the affected client and an endpoint, and then using a forged certificate to impersonate the endpoint. Depending on the configuration of the endpoint, an exploit could allow the attacker to view presentation content shared on it, modify any content being presented by the victim, or have access to call controls. This vulnerability does not affect cloud registered collaboration endpoints.

Synopsys hub-rest-api-python (aka blackduck on PyPI) version 0.0.25 - 0.0.52 does not validate SSL certificates in certain cases.

An incomplete SSL server certification validation vulnerability in the Trend Micro Security 2019 (v15) consumer family of products could allow an attacker to combine this vulnerability with another attack to trick an affected client into downloading a malicious update instead of the expected one. CWE-295: Improper server certificate verification in the communication with the update server.

The Apache Beam MongoDB connector in versions 2.10.0 to 2.16.0 has an option to disable SSL trust verification. However this configuration is not respected and the certificate verification disables trust verification in every case. This exclusion also gets registered globally which disables trust checking for any code running in the same JVM.

The HCL Traveler for Microsoft Outlook executable (HTMO.exe) is being flagged as potentially Malicious Software or an Unrecognized Application.

An issue was discovered in RIPE NCC RPKI Validator 3.x through 3.1-2020.07.06.14.28. Missing validation checks on CRL presence or CRL staleness in the X509-based RPKI certificate-tree validation procedure allow remote attackers to bypass intended access restrictions by using revoked certificates. NOTE: there may be counterarguments related to backwards compatibility

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.

In LemonLDAP::NG (aka lemonldap-ng) through 2.0.8, validity of the X.509 certificate is not checked by default when connecting to remote LDAP backends, because the default configuration of the Net::LDAPS module for Perl is used.

Couchbase Server Java SDK before 2.7.1.1 allows a potential attacker to forge an SSL certificate and pose as the intended peer. An attacker can leverage this flaw by crafting a cryptographically valid certificate that will be accepted by Java SDK's Netty component due to missing hostname verification.

Serverpod is an app and web server, built for the Flutter and Dart ecosystem. This bug bypassed the validation of TSL certificates on all none web HTTP clients in the `serverpod_client` package. Making them susceptible to a man in the middle attack against encrypted traffic between the client device and the server. An attacker would need to be able to intercept the traffic and highjack the connection to the server for this vulnerability to be used. Upgrading to version `1.2.6` resolves this issue.

Improper Certificate Validation vulnerability in the Online Threat Prevention module as used in Bitdefender Total Security allows an attacker to potentially bypass HTTP Strict Transport Security (HSTS) checks. This issue affects: Bitdefender Total Security versions prior to 25.0.7.29. Bitdefender Internet Security versions prior to 25.0.7.29. Bitdefender Antivirus Plus versions prior to 25.0.7.29.

em-imap 0.5 uses the library eventmachine in an insecure way that allows an attacker to perform a man-in-the-middle attack against users of the library. The hostname in a TLS server certificate is not verified.

A vulnerability has been identified in COMOS V10.6 (All versions < V10.6.1), COMOS V10.6 (All versions < V10.6.1), NX V2412 (All versions < V2412.8700), NX V2506 (All versions < V2506.6000), Simcenter 3D (All versions < V2506.6000), Simcenter Femap (All versions < V2506.0002), Solid Edge SE2025 (All versions < V225.0 Update 10), Solid Edge SE2026 (All versions < V226.0 Update 1). The IAM client in affected products is missing server certificate validation while establishing TLS connections to the authorization server. This could allow an attacker to perform a man-in-the-middle attack.

An issue was discovered in heinekingmedia StashCat before 1.5.18 for Android. No certificate pinning is implemented; therefore the attacker could issue a certificate for the backend and the application would not notice it.