Apache Tomcat Native 1.2.0 to 1.2.16 and 1.1.23 to 1.1.34 has a flaw that does not properly check OCSP pre-produced responses, which are lists (multiple entries) of certificate statuses. Subsequently, revoked client certificates may not be properly identified, allowing for users to authenticate with revoked certificates to connections that require mutual TLS. Users not using OCSP checks are not affected by this vulnerability.

The function `OCSP_basic_verify` verifies the signer certificate on an OCSP response. In the case where the (non-default) flag OCSP_NOCHECKS is used then the response will be positive (meaning a successful verification) even in the case where the response signing certificate fails to verify. It is anticipated that most users of `OCSP_basic_verify` will not use the OCSP_NOCHECKS flag. In this case the `OCSP_basic_verify` function will return a negative value (indicating a fatal error) in the case of a certificate verification failure. The normal expected return value in this case would be 0. This issue also impacts the command line OpenSSL "ocsp" application. When verifying an ocsp response with the "-no_cert_checks" option the command line application will report that the verification is successful even though it has in fact failed. In this case the incorrect successful response will also be accompanied by error messages showing the failure and contradicting the apparently successful result. Fixed in OpenSSL 3.0.3 (Affected 3.0.0,3.0.1,3.0.2).

PJSIP is a free and open source multimedia communication library written in C language implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. In version 2.10 and earlier, PJSIP transport can be reused if they have the same IP address + port + protocol. However, this is insufficient for secure transport since it lacks remote hostname authentication. Suppose we have created a TLS connection to `sip.foo.com`, which has an IP address `100.1.1.1`. If we want to create a TLS connection to another hostname, say `sip.bar.com`, which has the same IP address, then it will reuse that existing connection, even though `100.1.1.1` does not have certificate to authenticate as `sip.bar.com`. The vulnerability allows for an insecure interaction without user awareness. It affects users who need access to connections to different destinations that translate to the same address, and allows man-in-the-middle attack if attacker can route a connection to another destination such as in the case of DNS spoofing.

Odyssey passes to client unencrypted bytes from man-in-the-middle When Odyssey storage is configured to use the PostgreSQL server using 'trust' authentication with a 'clientcert' requirement or to use 'cert' authentication, a man-in-the-middle attacker can inject false responses to the client's first few queries. Despite the use of SSL certificate verification and encryption, Odyssey will pass these results to client as if they originated from valid server. This is similar to CVE-2021-23222 for PostgreSQL.

OkHttp before 2.7.4 and 3.x before 3.1.2 allows man-in-the-middle attackers to bypass certificate pinning by sending a certificate chain with a certificate from a non-pinned trusted CA and the pinned certificate.

When performing add-on updates, certificate chains terminating in non-built-in-roots were rejected (even if they were legitimately added by an administrator.) This could have caused add-ons to become out-of-date silently without notification to the user. This vulnerability affects Firefox ESR < 68.10, Firefox < 78, and Thunderbird < 68.10.0.

Certain NETGEAR devices are affected by Missing SSL Certificate Validation. This affects R7000 1.0.9.6_1.2.19 through 1.0.11.100_10.2.10, and possibly R6120, R7800, R6220, R8000, R6350, R9000, R6400, RAX120, R6400v2, RBR20, R6800, XR300, R6850, XR500, and R7000P.

The com.softphone.common package in the Grandstream Wave app 1.0.1.26 and earlier for Android does not properly validate SSL certificates, which allows man-in-the-middle attackers to spoof the Grandstream provisioning server via a crafted certificate.

IBM Cognos Analytics 11.2.0, 11.2.1, 11.2.2, 11.2.3, 11.2.4, 12.0.0, 12.0.1, and 12.0.2 is vulnerable to improper certificate validation when using the IBM Planning Analytics Data Source Connection. This could allow an attacker to spoof a trusted entity by interfering in the communication path between IBM Planning Analytics server and IBM Cognos Analytics server. IBM X-Force ID: 283364.

The RSS application on THOMSON THT741FTA 2.2.1 and Philips DTR3502BFTA DVB-T2 2.2.1 set-top boxes doesn't validate the SSL certificates of RSS servers, which allows a man-in-the-middle attacker to modify the data delivered to the client.

An issue existed in the handling of S-MIME certificates. This issue was addressed with improved validation of S-MIME certificates. This issue is fixed in macOS Mojave 10.14.4, Security Update 2019-002 High Sierra, Security Update 2019-002 Sierra. Processing a maliciously crafted mail message may lead to S/MIME signature spoofing.

The apt package in Debian jessie before 1.0.9.8.4, in Debian unstable before 1.4~beta2, in Ubuntu 14.04 LTS before 1.0.1ubuntu2.17, in Ubuntu 16.04 LTS before 1.2.15ubuntu0.2, and in Ubuntu 16.10 before 1.3.2ubuntu0.1 allows man-in-the-middle attackers to bypass a repository-signing protection mechanism by leveraging improper error handling when validating InRelease file signatures.

electron-packager is a command line tool that packages Electron source code into `.app` and `.exe` packages. along with Electron. The `--strict-ssl` command line option in electron-packager >= 5.2.1 <= 6.0.0 || >=6.0.0 <= 6.0.2 defaults to false if not explicitly set to true. This could allow an attacker to perform a man in the middle attack.

jxbrowser in TI Code Composer Studio IDE 8.x through 10.x before 10.1.1 does not verify X.509 certificates for HTTPS.

Mailvelope prior to 3.3.0 accepts or operates with invalid PGP public keys: Mailvelope allows importing keys that contain users without a valid self-certification. Keys that are obviously invalid are not rejected during import. An attacker that is able to get a victim to import a manipulated key could claim to have signed a message that originates from another person.

On 2N Access Unit 2.0 2.31.0.40.5 devices, an attacker can pose as the web relay for a man-in-the-middle attack.

PJSIP is a free and open source multimedia communication library written in C. Prior to version 2.17, on GnuTLS builds, the SIP TLS transport (sip_transport_tls) can accept connections with invalid or untrusted certificates even when the application explicitly enables certificate verification via verify_server = PJ_TRUE or verify_client = PJ_TRUE. This issue has been patched in version 2.17.

The fix for CVE-2025-68161 https://logging.apache.org/security.html#CVE-2025-68161 was incomplete: it addressed hostname verification only when enabled via the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.html#log4j2.sslVerifyHostName system property, but not when configured through the verifyHostName https://logging.apache.org/log4j/2.x/manual/appenders/network.html#SslConfiguration-attr-verifyHostName attribute of the <Ssl> element. Although the verifyHostName configuration attribute was introduced in Log4j Core 2.12.0, it was silently ignored in all versions through 2.25.3, leaving TLS connections vulnerable to interception regardless of the configured value. A network-based attacker may be able to perform a man-in-the-middle attack when all of the following conditions are met: * An SMTP, Socket, or Syslog appender is in use. * TLS is configured via a nested <Ssl> element. * The attacker can present a certificate issued by a CA trusted by the appender's configured trust store, or by the default Java trust store if none is configured. This issue does not affect users of the HTTP appender, which uses a separate verifyHostname https://logging.apache.org/log4j/2.x/manual/appenders/network.html#HttpAppender-attr-verifyHostName attribute that was not subject to this bug and verifies host names by default. Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue.

Botan is a C++ cryptography library. Prior to version 3.11.0, during processing of an X.509 certificate path using name constraints which restrict the set of allowable DNS names, if no subject alternative name is defined in the end-entity certificate Botan would check that the CN was allowed by the DNS name constraints, even though this check is technically not required by RFC 5280. However this check failed to account for the possibility of a mixed-case CN. Thus a certificate with CN=Sub.EVIL.COM and no subject alternative name would bypasses an excludedSubtrees constraint for evil.com because the comparison is case-sensitive. This issue has been patched in version 3.11.0.

IBM BigFix Remote Control before Interim Fix pack 9.1.2-TIV-IBRC912-IF0001 improperly allows self-signed certificates, which might allow remote attackers to conduct spoofing attacks via unspecified vectors. IBM X-Force ID: 105200.

The TLS protocol 1.2 and earlier, when a DHE_EXPORT ciphersuite is enabled on a server but not on a client, does not properly convey a DHE_EXPORT choice, which allows man-in-the-middle attackers to conduct cipher-downgrade attacks by rewriting a ClientHello with DHE replaced by DHE_EXPORT and then rewriting a ServerHello with DHE_EXPORT replaced by DHE, aka the "Logjam" issue.

Hostname verification in Apache ZooKeeper ZKTrustManager falls back to reverse DNS (PTR) when IP SAN validation fails, allowing attackers who control or spoof PTR records to impersonate ZooKeeper servers or clients with a valid certificate for the PTR name. It's important to note that attacker must present a certificate which is trusted by ZKTrustManager which makes the attack vector harder to exploit. Users are recommended to upgrade to version 3.8.6 or 3.9.5, which fixes this issue by introducing a new configuration option to disable reverse DNS lookup in client and quorum protocols.

Restkit allows man-in-the-middle attackers to spoof TLS servers by leveraging use of the ssl.wrap_socket function in Python with the default CERT_NONE value for the cert_reqs argument.

Oracle MySQL before 5.7.3, Oracle MySQL Connector/C (aka libmysqlclient) before 6.1.3, and MariaDB before 5.5.44 use the --ssl option to mean that SSL is optional, which allows man-in-the-middle attackers to spoof servers via a cleartext-downgrade attack, aka a "BACKRONYM" attack.

rhnreg_ks in Red Hat Network Client Tools (aka rhn-client-tools) on Red Hat Gluster Storage 2.1 and Enterprise Linux (RHEL) 5, 6, and 7 does not properly validate hostnames in X.509 certificates from SSL servers, which allows remote attackers to prevent system registration via a man-in-the-middle attack.

vdsm and vdsclient does not validate certficate hostname from another vdsm which could facilitate a man-in-the-middle attack

The esets_daemon service in ESET Endpoint Antivirus for macOS before 6.4.168.0 and Endpoint Security for macOS before 6.4.168.0 does not properly verify X.509 certificates from the edf.eset.com SSL server, which allows man-in-the-middle attackers to spoof this server and provide crafted responses to license activation requests via a self-signed certificate. NOTE: this issue can be combined with CVE-2016-0718 to execute arbitrary code remotely as root.

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.

The libwww-perl LWP::Protocol::https module 6.04 through 6.06 for Perl, when using IO::Socket::SSL as the SSL socket class, allows attackers to disable server certificate validation via the (1) HTTPS_CA_DIR or (2) HTTPS_CA_FILE environment variable.

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.

IBM QRadar SIEM 7.5 could allow an unauthorized user to perform unauthorized actions due to improper certificate validation. IBM X-Force ID: 275706.

In fence-agents before 4.0.17 does not verify remote SSL certificates in the fence_cisco_ucs.py script which can potentially allow for man-in-the-middle attackers to spoof SSL servers via arbitrary SSL certificates.

Amazon SageMaker Python SDK before v3.1.1 or v2.256.0 disables TLS certificate verification for HTTPS connections made by the service when a Triton Python model is imported, incorrectly allowing for requests with invalid and self-signed certificates to succeed.

When using `CURLOPT_PINNEDPUBLICKEY` option with libcurl or `--pinnedpubkey` with the curl tool,curl should check the public key of the server certificate to verify the peer. This check was skipped in a certain condition that would then make curl allow the connection without performing the proper check, thus not noticing a possible impostor. To skip this check, the connection had to be done with QUIC with ngtcp2 built to use GnuTLS and the user had to explicitly disable the standard certificate verification.

ovirt-engine-sdk-python before 3.4.0.7 and 3.5.0.4 does not verify that the hostname of the remote endpoint matches the Common Name (CN) or subjectAltName as specified by its x.509 certificate in a TLS/SSL session. This could allow man-in-the-middle attackers to spoof remote endpoints via an arbitrary valid certificate.

Google Chrome caches TLS sessions before certificate validation occurs.

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.

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`.

Nimble is a package manager for the Nim programming language. In Nim release versions before versions 1.2.10 and 1.4.4, "nimble refresh" fetches a list of Nimble packages over HTTPS by default. In case of error it falls back to a non-TLS URL http://irclogs.nim-lang.org/packages.json. An attacker able to perform MitM can deliver a modified package list containing malicious software packages. If the packages are installed and used the attack escalates to untrusted code execution.

HTTPSConnections in OpenStack Keystone 2013, OpenStack Compute 2013.1, and possibly other OpenStack components, fail to validate server-side SSL certificates.

A certificate validation issue was addressed. This issue is fixed in iOS 14.5 and iPadOS 14.5. An attacker in a privileged network position may be able to alter network traffic.

The Chase mobile banking application for Android does not verify that the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate, related to overriding the default X509TrustManager. NOTE: this vulnerability was fixed in the summer of 2012, but the version number was not changed or is not known.

vdsm: certificate generation upon node creation allowing vdsm to start and serve requests from anyone who has a matching key (and certificate)

Incorrect certificate validation in InvokeHTTP on Apache NiFi MiNiFi C++ versions 0.13 to 0.14 allows an intermediary to present a forged certificate during TLS handshake negotation. The Disable Peer Verification property of InvokeHTTP was effectively flipped, disabling verification by default, when using HTTPS. Mitigation: Set the Disable Peer Verification property of InvokeHTTP to true when using MiNiFi C++ versions 0.13.0 or 0.14.0. Upgrading to MiNiFi C++ 0.15.0 corrects the default behavior.

A flaw in Mozilla's embedded certificate code might allow web sites to install root certificates on devices without user approval.

Nessus AMI versions 8.12.0 and earlier were found to either not validate, or incorrectly validate, a certificate which could allow an attacker to spoof a trusted entity by using a man-in-the-middle (MITM) attack.

IBM Security Secret Server prior to 10.9 could allow an attacker to bypass SSL security due to improper certificate validation. IBM X-Force ID: 178180.

An issue was discovered in Mbed TLS before 2.24.0. The verification of X.509 certificates when matching the expected common name (the cn argument of mbedtls_x509_crt_verify) with the actual certificate name is mishandled: when the subjecAltName extension is present, the expected name is compared to any name in that extension regardless of its type. This means that an attacker could impersonate a 4-byte or 16-byte domain by getting a certificate for the corresponding IPv4 or IPv6 address (this would require the attacker to control that IP address, though).

An issue was discovered in Arm Mbed TLS before 2.24.0. It incorrectly uses a revocationDate check when deciding whether to honor certificate revocation via a CRL. In some situations, an attacker can exploit this by changing the local clock.

Apache Libcloud before 0.11.1 uses an incorrect regular expression during verification of whether the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via a crafted certificate.