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.

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 curl URL parser wrongly accepts percent-encoded URL separators like '/'when decoding the host name part of a URL, making it a *different* URL usingthe wrong host name when it is later retrieved.For example, a URL like `http://example.com%2F127.0.0.1/`, would be allowed bythe parser and get transposed into `http://example.com/127.0.0.1/`. This flawcan be used to circumvent filters, checks and more.

libcurl would reuse a previously created connection even when some mTLS config related option had been changed that should have prohibited reuse. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, some TLS settings related to client certificates were left out from the configuration match checks, making them match too easily. In particular options related to the private key.

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.

libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. An easy handle that first uses default native CA trust can continue trusting the native platform store after the application switches that same handle to custom CA material for a later transfer.

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.

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.

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).

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 fails to detect OCSP problems and instead wrongly consider the response as fine.

A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not.

When doing TLS related transfers with reused easy or multi handles and altering the `CURLSSLOPT_NO_PARTIALCHAIN` option, libcurl could accidentally reuse a CA store cached in memory for which the partial chain option was reversed. Contrary to the user's wishes and expectations. This could make libcurl find and accept a trust chain that it otherwise would not.

A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool. If an initial transfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request to that same host bypasses the TLS requirement and instead transmit data unencrypted.

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`.

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.

libcurl supports *pinning* of the server certificate public key for HTTPS transfers. Due to an omission, this check is not performed when connecting with QUIC for HTTP/3, when the TLS backend is wolfSSL. Documentation says the option works with wolfSSL, failing to specify that it does not for QUIC and HTTP/3. Since pinning makes the transfer succeed if the pin is fine, users could unwittingly connect to an impostor server without noticing.

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.

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.

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.

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."

Opera before 10.00 does not check all intermediate X.509 certificates for revocation, which makes it easier for remote SSL servers to bypass validation of the certificate chain via a revoked certificate.

On Darwin, user's trust preferences for root certificates were not honored. If the user had a root certificate loaded in their Keychain that was explicitly not trusted, a Go program would still verify a connection using that root certificate.

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 4.10.11 and 5.2.2, the certificate in the Parse Server Apple Game Center auth adapter not validated. As a result, authentication could potentially be bypassed by making a fake certificate accessible via certain Apple domains and providing the URL to that certificate in an authData object. Versions 4.0.11 and 5.2.2 prevent this by introducing a new `rootCertificateUrl` property to the Parse Server Apple Game Center auth adapter which takes the URL to the root certificate of Apple's Game Center authentication certificate. If no value is set, the `rootCertificateUrl` property defaults to the URL of the current root certificate as of May 27, 2022. Keep in mind that the root certificate can change at any time and that it is the developer's responsibility to keep the root certificate URL up-to-date when using the Parse Server Apple Game Center auth adapter. There are no known workarounds for this issue.

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.

If the MongoDB Server running on Windows or macOS is configured to use TLS with a specific set of configuration options that are already known to work securely in other platforms (e.g. Linux), it is possible that client certificate validation may not be in effect, potentially allowing client to establish a TLS connection with the server that supplies any certificate. This issue affect all MongoDB Server v6.3 versions, MongoDB Server v5.0 versions v5.0.0 to v5.0.14 and all MongoDB Server v4.4 versions.

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.

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.

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

libgrss through 0.7.0 fails to perform TLS certificate verification when downloading feeds, allowing remote attackers to manipulate the contents of feeds without detection. This occurs because of the default behavior of SoupSessionSync.

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.

Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, S/MIME signature verification did not validate the certificate trust chain (checkChain: false). Any email signed with a self-signed or untrusted certificate was displayed as having a valid signature. This vulnerability is fixed in 1.4.11.

When verifying a certificate chain containing excluded DNS constraints, these constraints are not correctly applied to wildcard DNS SANs which use a different case than the constraint. This only affects validation of otherwise trusted certificate chains, issued by a root CA in the VerifyOptions.Roots CertPool, or in the system certificate pool.

rfc3161-client is a Python library implementing the Time-Stamp Protocol (TSP) described in RFC 3161. Prior to 1.0.6, an Authorization Bypass vulnerability in rfc3161-client's signature verification allows any attacker to impersonate a trusted TimeStamping Authority (TSA). By exploiting a logic flaw in how the library extracts the leaf certificate from an unordered PKCS#7 bag of certificates, an attacker can append a spoofed certificate matching the target common_name and Extended Key Usage (EKU) requirements. This tricks the library into verifying these authorization rules against the forged certificate while validating the cryptographic signature against an actual trusted TSA (such as FreeTSA), thereby bypassing the intended TSA authorization pinning entirely. This vulnerability is fixed in 1.0.6.

IMAPFilter through 2.6.12 does not validate the hostname in an SSL certificate.

Pion DTLS is a Go implementation of Datagram Transport Layer Security. Prior to version 2.1.5, a DTLS Client could provide a Certificate that it doesn't posses the private key for and Pion DTLS wouldn't reject it. This issue affects users that are using Client certificates only. The connection itself is still secure. The Certificate provided by clients can't be trusted when using a Pion DTLS server prior to version 2.1.5. Users should upgrade to version 2.1.5 to receive a patch. There are currently no known workarounds.

Apache Thrift Java client library versions 0.5.0 through 0.11.0 can bypass SASL negotiation isComplete validation in the org.apache.thrift.transport.TSaslTransport class. An assert used to determine if the SASL handshake had successfully completed could be disabled in production settings making the validation incomplete.

iSmartAlarm cube devices have an SSL Certificate Validation Vulnerability.

Improper Input Validation vulnerability in Apache Tomcat Native, Apache Tomcat. When using an OCSP responder, Tomcat Native (and Tomcat's FFM port of the Tomcat Native code) did not complete verification or freshness checks on the OCSP response which could allow certificate revocation to be bypassed. This issue affects Apache Tomcat Native:  from 1.3.0 through 1.3.4, from 2.0.0 through 2.0.11; Apache Tomcat: from 11.0.0-M1 through 11.0.17, from 10.1.0-M7 through 10.1.51, from 9.0.83 through 9.0.114. The following versions were EOL at the time the CVE was created but are known to be affected: from 1.1.23 through 1.1.34, from 1.2.0 through 1.2.39. Older EOL versions are not affected. Apache Tomcat Native users are recommended to upgrade to versions 1.3.5 or later or 2.0.12 or later, which fix the issue. Apache Tomcat users are recommended to upgrade to versions 11.0.18 or later, 10.1.52 or later or 9.0.115 or later which fix the issue.

X.509 trust-chain bypass (path-depth exhaustion) in the OpenSSL compatibility certificate verifier (wolfSSL_X509_verify_cert()). This affects only builds with --enable-opensslextra whose application calls X509_verify_cert() with caller-supplied untrusted intermediates; for those users it is critical, otherwise the library is unaffected. Native wolfSSL TLS/DTLS usage is not impacted. X509_verify_cert() returned success based only on the last verified link rather than on reaching a trust anchor: when the supplied chain is deeper than the verifier's maximum path depth (default 100), path building runs out of depth while still walking untrusted intermediates and the chain is accepted even though it never reaches a configured trust anchor, allowing acceptance of an attacker-controlled certificate. The default TLS handshake (WOLFSSL_VERIFY_PEER) is not affected; only applications doing manual or deferred verification through this API are.

Jenkins Proxmox Plugin 0.6.0 and earlier disables SSL/TLS certificate validation globally for the Jenkins controller JVM when configured to ignore SSL/TLS issues.

GnuTLS before 3.3.13 does not validate that the signature algorithms match when importing a certificate.

EMC RSA BSAFE Micro Edition Suite (MES) 4.0.x before 4.0.8 and 4.1.x before 4.1.3, RSA BSAFE Crypto-J before 6.2, RSA BSAFE SSL-J before 6.2, and RSA BSAFE SSL-C 2.8.9 and earlier do not enforce certain constraints on certificate data, which allows remote attackers to defeat a fingerprint-based certificate-blacklist protection mechanism by including crafted data within a certificate's unsigned portion, a similar issue to CVE-2014-8275.

In wolfSSL before 5.2.0, a TLS 1.3 server cannot properly enforce a requirement for mutual authentication. A client can simply omit the certificate_verify message from the handshake, and never present a certificate.

An issue was discovered in Hybrid Group Gobot before 1.13.0. The mqtt subsystem skips verification of root CA certificates by default.

wolfssl before 3.2.0 does not properly issue certificates for a server's hostname.

wolfssl before 3.2.0 does not properly authorize CA certificate for signing other certificates.

A bug in PSL validation logic in Apache HttpClient 5.4.x disables domain checks, affecting cookie management and host name verification. Discovered by the Apache HttpClient team. Fixed in the 5.4.3 release

A vulnerability in the Secure Sockets Layer (SSL) Virtual Private Network (VPN) Client Certificate Authentication feature for Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, remote attacker to establish an SSL VPN connection and bypass certain SSL certificate verification steps. The vulnerability is due to incorrect verification of the SSL Client Certificate. An attacker could exploit this vulnerability by connecting to the ASA VPN without a proper private key and certificate pair. A successful exploit could allow the attacker to establish an SSL VPN connection to the ASA when the connection should have been rejected. This vulnerability affects Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Software that is running on the following Cisco products: 3000 Series Industrial Security Appliances (ISA), ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Adaptive Security Virtual Appliances (ASAv), Firepower 4110 Security Appliances, Firepower 9300 ASA Security Modules. Cisco Bug IDs: CSCvg40155.

The transit path validation code in Heimdal before 7.3 might allow attackers to bypass the capath policy protection mechanism by leveraging failure to add the previous hop realm to the transit path of issued tickets.