In Splunk Enterprise and Universal Forwarder versions before 9.0, the Splunk command-line interface (CLI) did not validate TLS certificates while connecting to a remote Splunk platform instance by default. After updating to version 9.0, see Configure TLS host name validation for the Splunk CLI https://docs.splunk.com/Documentation/Splunk/9.0.0/Security/EnableTLSCertHostnameValidation#Configure_TLS_host_name_validation_for_the_Splunk_CLI to enable the remediation. The vulnerability does not affect the Splunk Cloud Platform. At the time of publishing, we have no evidence of exploitation of this vulnerability by external parties. The issue requires conditions beyond the control of a potential bad actor such as a machine-in-the-middle attack. Hence, Splunk rates the complexity of the attack as High.

When using Ingest Actions to configure a destination that resides on Amazon Simple Storage Service (S3) in Splunk Web, TLS certificate validation is not correctly performed and tested for the destination. The vulnerability only affects connections between Splunk Enterprise and an Ingest Actions Destination through Splunk Web and only applies to environments that have configured TLS certificate validation. It does not apply to Destinations configured directly in the outputs.conf configuration file. The vulnerability affects Splunk Enterprise version 9.0.0 and does not affect versions below 9.0.0, including the 8.1.x and 8.2.x versions.

A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that could cause HSTS functionality fail when multiple URLs are requested serially. Using its HSTS support, curl can be instructed to use HTTPS instead of usingan insecure clear-text HTTP step even when HTTP is provided in the URL. ThisHSTS mechanism would however surprisingly be ignored by subsequent transferswhen done on the same command line because the state would not be properlycarried on.

Splunk Enterprise peers in Splunk Enterprise versions before 9.0 and Splunk Cloud Platform versions before 8.2.2203 did not validate the TLS certificates during Splunk-to-Splunk communications by default. Splunk peer communications configured properly with valid certificates were not vulnerable. However, an attacker with administrator credentials could add a peer without a valid certificate and connections from misconfigured nodes without valid certificates did not fail by default. For Splunk Enterprise, update to Splunk Enterprise version 9.0 and Configure TLS host name validation for Splunk-to-Splunk communications (https://docs.splunk.com/Documentation/Splunk/9.0.0/Security/EnableTLSCertHostnameValidation) to enable the remediation.

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.

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.

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.

Splunk-SDK-Python before 1.6.6 does not properly verify untrusted TLS server certificates, which could result in man-in-the-middle attacks.

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.

Splunk Enterprise peers in Splunk Enterprise versions before 9.0 and Splunk Cloud Platform versions before 8.2.2203 did not validate the TLS certificates during Splunk-to-Splunk communications by default. Splunk peer communications configured properly with valid certificates were not vulnerable. However, an attacker with administrator credentials could add a peer without a valid certificate and connections from misconfigured nodes without valid certificates did not fail by default. For Splunk Enterprise, update to Splunk Enterprise version 9.0 and Configure TLS host name validation for Splunk-to-Splunk communications (https://docs.splunk.com/Documentation/Splunk/9.0.0/Security/EnableTLSCertHostnameValidation) to enable the remediation.

Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows OCSP designated-responder authorization bypass via missing signature verification. The OCSP response validation in public_key:pkix_ocsp_validate/5 does not verify that a CA-designated responder certificate was cryptographically signed by the issuing CA. Instead, it only checks that the responder certificate's issuer name matches the CA's subject name and that the certificate has the OCSPSigning extended key usage. An attacker who can intercept or control OCSP responses can create a self-signed certificate with a matching issuer name and the OCSPSigning EKU, and use it to forge OCSP responses that mark revoked certificates as valid. This affects SSL/TLS clients using OCSP stapling, which may accept connections to servers with revoked certificates, potentially transmitting sensitive data to compromised servers. Applications using the public_key:pkix_ocsp_validate/5 API directly are also affected, with impact depending on usage context. This vulnerability is associated with program files lib/public_key/src/pubkey_ocsp.erl and program routines pubkey_ocsp:is_authorized_responder/3. This issue affects OTP from OTP 27.0 until OTP 28.4.2 and 27.3.4.10 corresponding to public_key from 1.16 until 1.20.3 and 1.17.1.2, and ssl from 11.2 until 11.5.4 and 11.2.12.7.

core/imap/MCIMAPSession.cpp in Canary Mail before 3.22 has Missing SSL Certificate Validation for IMAP in STARTTLS mode.

The ASUS Vivobaby application before 1.1.09 for Android has Missing SSL Certificate Validation.

A vulnerability has been identified in SINUMERIK Analyse MyCondition (All versions), SINUMERIK Analyze MyPerformance (All versions), SINUMERIK Analyze MyPerformance /OEE-Monitor (All versions), SINUMERIK Analyze MyPerformance /OEE-Tuning (All versions), SINUMERIK Integrate Client 02 (All versions >= V02.00.12 < 02.00.18), SINUMERIK Integrate Client 03 (All versions >= V03.00.12 < 03.00.18), SINUMERIK Integrate Client 04 (V04.00.02 and all versions >= V04.00.15 < 04.00.18), SINUMERIK Integrate for Production 4.1 (All versions < V4.1 SP10 HF3), SINUMERIK Integrate for Production 5.1 (V5.1), SINUMERIK Manage MyMachines (All versions), SINUMERIK Manage MyMachines /Remote (All versions), SINUMERIK Manage MyMachines /Spindel Monitor (All versions), SINUMERIK Manage MyPrograms (All versions), SINUMERIK Manage MyResources /Programs (All versions), SINUMERIK Manage MyResources /Tools (All versions), SINUMERIK Manage MyTools (All versions), SINUMERIK Operate V4.8 (All versions < V4.8 SP8), SINUMERIK Operate V4.93 (All versions < V4.93 HF7), SINUMERIK Operate V4.94 (All versions < V4.94 HF5), SINUMERIK Optimize MyProgramming /NX-Cam Editor (All versions). Due to an error in a third-party dependency the ssl flags used for setting up a TLS connection to a server are overwitten with wrong settings. This results in a missing validation of the server certificate and thus in a possible TLS MITM szenario.

Improper certificate validation in Ivanti EPMM before versions 12.6.1.1, 12.7.0.1, and 12.8.0.1 allows a remote unauthenticated attacker to enroll a device belonging to a restricted set of unenrolled devices, leading to information disclosure about EPMM appliance and impacting on the integrity of the newly enrolled device identity.

Alist is a file list program that supports multiple storages, powered by Gin and Solidjs. Prior to version 3.57.0, the application disables TLS certificate verification by default for all outgoing storage driver communications, making the system vulnerable to Man-in-the-Middle (MitM) attacks. This enables the complete decryption, theft, and manipulation of all data transmitted during storage operations, severely compromising the confidentiality and integrity of user data. This issue has been patched in version 3.57.0.

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.

In Botan before 2.19.3, it is possible to forge OCSP responses due to a certificate verification error. This issue was introduced in Botan 1.11.34 (November 2016).

A potential vulnerability has been identified in HP Remote Graphics Software’s certificate authentication process version 7.5.0 and earlier.

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)

FastNetMon Community Edition through 1.2.9 does not verify TLS certificates on outbound HTTPS connections. The execute_web_request_secure() function in src/fast_library.cpp creates a boost::asio::ssl::context with tls_client mode and calls set_default_verify_paths() to load CA certificates, but never calls set_verify_mode(boost::asio::ssl::verify_peer). Without this call, OpenSSL performs the TLS handshake without validating the server's certificate chain, making all HTTPS connections vulnerable to man-in-the-middle attacks. This function is used for telemetry reporting to community-stats.fastnetmon.com, which sends system information including CPU model, kernel version, traffic statistics, and software configuration. An attacker can intercept and modify this data or redirect it to a malicious server.

A weakness in the certificate validation logic of the deprecated IKEv1 key exchange may allow an unauthenticated attacker positioned as a man-in-the-middle to bypass certificate validation in VPN site-to-site connections that use certificate-based authentication. Successful exploitation could allow interception or modification of traffic traversing the VPN tunnel.

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.

Windows Secure Channel Spoofing Vulnerability

An Improper Certificate Validation vulnerability in the OPC-UA client and ANSL over TLS client used in Automation Studio versions before 6.5 could allow an unauthenticated attacker on the network to position themselves to intercept and interfere with data exchanges.

A flaw was found in gnutls. This vulnerability occurs because permitted name constraints were incorrectly ignored when previous Certificate Authorities (CAs) only had excluded name constraints. A remote attacker could exploit this to bypass critical name constraint checks during certificate validation. This bypass could lead to the acceptance of invalid certificates, potentially enabling spoofing or man-in-the-middle attacks against affected systems.

Improper Certificate Validation in Checkmk Exchange plugin MikroTik allows attackers in MitM position to intercept traffic. This issue affects MikroTik: from 2.0.0 through 2.5.5, from 0.4a_mk through 2.0a.

Impact: undici's ProxyAgent silently drops the requestTls option when configured with a SOCKS5 proxy URI (socks5:// or socks://). The target HTTPS connection through the SOCKS5 tunnel falls back to Node's default trust store, ignoring user-configured ca, cert, key, rejectUnauthorized, and servername settings. Applications that pin to an internal or corporate CA via requestTls.ca will, when their proxy URI is SOCKS5, get the default Mozilla CA bundle as the trust anchor instead. Any cert signed by any publicly-trusted CA for the target hostname is accepted, breaking the intended pin and enabling MITM read and tamper of the HTTPS exchange. Affected applications are those that use undici's ProxyAgent (or Socks5ProxyAgent directly) with SOCKS5 AND rely on requestTls for TLS scope restriction. The bug was introduced in undici 7.23.0 when SOCKS5 support was added. Patches: Upgrade to undici v7.28.0 or v8.5.0. Workarounds: No workaround is available within the SOCKS5 path. If a SOCKS5 proxy with TLS scope restriction is required and an upgrade is not yet possible, route the traffic through an HTTP-proxy ProxyAgent instead, where requestTls is honored correctly.

Envoy is an open source edge and service proxy, designed for cloud-native applications. Envoy's tls allows re-use when some cert validation settings have changed from their default configuration. The only workaround for this issue is to ensure that default tls settings are used. Users are advised to upgrade.

An Improper Certificate Validation in Ivanti EPMM before versions 12.6.1.1, 12.7.0.1, and 12.8.0.1 allows a remote unauthenticated attacker to impersonate registered Sentry hosts and obtain valid CA-signed client certificates.

An Improper Certificate Validation weakness in the Juniper Networks Junos OS allows an attacker to perform Person-in-the-Middle (PitM) attacks when a system script is fetched from a remote source at a specified HTTPS URL, which may compromise the integrity and confidentiality of the device. The following command can be executed by an administrator via the CLI to refresh a script from a remote location, which is affected from this vulnerability: >request system scripts refresh-from (commit | event | extension-service | op | snmp) file filename url <https-url> This issue affects: Juniper Networks Junos OS All versions prior to 18.4R2-S9, 18.4R3-S9; 19.1 versions prior to 19.1R2-S3, 19.1R3-S7; 19.2 versions prior to 19.2R1-S7, 19.2R3-S3; 19.3 versions prior to 19.3R3-S4; 19.4 versions prior to 19.4R3-S7; 20.1 versions prior to 20.1R2-S2, 20.1R3; 20.2 versions prior to 20.2R3; 20.3 versions prior to 20.3R2-S1, 20.3R3; 20.4 versions prior to 20.4R2; 21.1 versions prior to 21.1R1-S1, 21.1R2.

Missing hash/digest size and OID checks allow digests smaller than allowed when verifying ECDSA certificates, or smaller than is appropriate for the relevant key type, to be accepted by signature verification functions. This could lead to reduced security of ECDSA certificate-based authentication if the public CA key used is also known. This affects ECDSA/ECC verification when EdDSA or ML-DSA is also enabled.

A flaw was found in assisted-migration-agent. The application hardcodes insecure Transport Layer Security (TLS) connections when communicating with vCenter. This vulnerability allows a Man-in-the-Middle (MITM) attacker to intercept and harvest vCenter administrator credentials. This can lead to unauthorized access to vCenter.

An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. The X.509 certificate validation can be skipped for a TLS-based e-mail server.

Envoy is an open source edge and service proxy, designed for cloud-native applications. The default_validator.cc implementation used to implement the default certificate validation routines has a "type confusion" bug when processing subjectAltNames. This processing allows, for example, an rfc822Name or uniformResourceIndicator to be authenticated as a domain name. This confusion allows for the bypassing of nameConstraints, as processed by the underlying OpenSSL/BoringSSL implementation, exposing the possibility of impersonation of arbitrary servers. As a result Envoy will trust upstream certificates that should not be trusted.

A vulnerability in the certificate validation of Cisco&nbsp;Expressway-C and Cisco&nbsp;TelePresence VCS could allow an unauthenticated, remote attacker to gain unauthorized access to sensitive data.&nbsp;&nbsp;The vulnerability is due to a lack of validation of the SSL server certificate that an affected device receives when it establishes a connection to a Cisco&nbsp;Unified Communications Manager device. An attacker could exploit this vulnerability by using a man-in-the-middle technique to intercept the traffic between the devices, and then using a self-signed certificate to impersonate the endpoint. A successful exploit could allow the attacker to view the intercepted traffic in clear text or alter the contents of the traffic. Note: Cisco&nbsp;Expressway-E is not affected by this vulnerability.Cisco&nbsp;has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

In OCaml-TLS before 2.1.0, the server implementation does insufficient checks of the certificate provided by the client (when doing client authentication), which allows impersonation with certificates that are not meant for client authentication (because of KeyUsage and ExtendedKeyUsage).

In OCaml-TLS before 2.1.0, the client implementation does insufficient checks of the certificate provided by the server, which allows impersonation with certificates that are not meant for server authentication (because of KeyUsage and ExtendedKeyUsage).

The ASUS HiVivo aspplication before 5.6.27 for ASUS Watch has Missing SSL Certificate Validation.

A certificate validation issue existed when processing administrator added certificates. This issue was addressed with improved certificate validation. This issue is fixed in iOS 13.6 and iPadOS 13.6, macOS Catalina 10.15.6, tvOS 13.4.8, watchOS 6.2.8. An attacker may have been able to impersonate a trusted website using shared key material for an administrator added certificate.

Previously, a revoked 'SignatureKey' belonging to a CA was not correctly checked for revocation. Now, both the 'key' and 'key.SignatureKey' are checked for @revoked.

CKAN is an open-source DMS (data management system) for powering data hubs and data portals. Prior to 2.10.10 and 2.11.5, the configured SMTP server may be spoofed with any certificate (e.g. self-signed), leaving credentials and all emails sent open to MITM attacks. This vulnerability is fixed in 2.10.10 and 2.11.5.

Accepting arbitrary Subject Alternative Name (SAN) types, unless a PKI is specifically defined to use a particular SAN type, can result in bypassing name-constrained intermediates. Node.js < 12.22.9, < 14.18.3, < 16.13.2, and < 17.3.1 was accepting URI SAN types, which PKIs are often not defined to use. Additionally, when a protocol allows URI SANs, Node.js did not match the URI correctly.Versions of Node.js with the fix for this disable the URI SAN type when checking a certificate against a hostname. This behavior can be reverted through the --security-revert command-line option.

When configured to use an SSL bundle, Spring Boot's RabbitMQ auto-configuration does not perform hostname verification when connecting to the RabbitMQ broker. Affected: Spring Boot 4.0.0–4.0.5 (fix 4.0.6), 3.5.0–3.5.13 (fix 3.5.14) per vendor advisory.

Improper certificate validation in the identity provider connection components in Amazon Athena ODBC driver before 2.1.0.0 might allow a man-in-the-middle threat actor to intercept authentication credentials due to insufficient default transport security when connecting to identity providers. This only applies to connections with external identity providers and does not apply to connections with Athena. To remediate this issue, users should upgrade to version 2.1.0.0.

Forge (also called `node-forge`) is a native implementation of Transport Layer Security in JavaScript. Prior to version 1.4.0, `pki.verifyCertificateChain()` does not enforce RFC 5280 basicConstraints requirements when an intermediate certificate lacks both the `basicConstraints` and `keyUsage` extensions. This allows any leaf certificate (without these extensions) to act as a CA and sign other certificates, which node-forge will accept as valid. Version 1.4.0 patches the issue.

A vulnerability has been identified in SINUMERIK Edge (All versions < V3.2). The affected software does not properly validate the server certificate when initiating a TLS connection. This could allow an attacker to spoof a trusted entity by interfering in the communication path between the client and the intended server.

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

OpenVPN 3 Core Library version 3.6 and 3.6.1 allows a man-in-the-middle attacker to bypass the certificate authentication by issuing an unrelated server certificate using the same hostname found in the verify-x509-name option in a client configuration.

Affected versions of CODESYS Git in Versions prior to V1.1.0.0 lack certificate validation in HTTPS handshakes. CODESYS Git does not implement certificate validation by default, so it does not verify that the server provides a valid and trusted HTTPS certificate. Since the certificate of the server to which the connection is made is not properly verified, the server connection is vulnerable to a man-in-the-middle attack.