Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-08-01T12:22:16 FreeRDP: FreeRDP: Weakens TLS server authentication due to improper wildcard certificate hostname validation 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N CWE-295

FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains an improper certificate hostname validation vulnerability. The TLS hostname matcher (tls_match_hostname() in libfreerdp/crypto/tls.c) treats a wildcard pattern such as *.example.com as matching any hostname ending in .example.com, so it incorrectly accepts a wildcard certificate for multi-label subdomains like a.b.example.com (which OpenSSL's X509_check_host() rejects). This weakens TLS server authentication under wildcard-certificate conditions.

A flaw was found in FreeRDP, a free implementation of the Remote Desktop Protocol (RDP). The software's Transport Layer Security (TLS) hostname matcher incorrectly validates wildcard certificates, allowing it to accept certificates for multi-label subdomains that should not be covered. This vulnerability could enable a remote attacker to impersonate a legitimate server, potentially compromising the authenticity of the connection. This weakens the overall security of TLS server authentication.

This Moderate flaw in FreeRDP weakens TLS server authentication by incorrectly validating wildcard certificates. The client's TLS hostname matcher accepts multi-label subdomains (e.g., a.b.example.com) for a single-level wildcard (e.g., *.example.com), which deviates from standard OpenSSL behavior. This could allow a malicious RDP server to impersonate a legitimate server if a client attempts to connect to a subdomain covered by an improperly validated wildcard certificate. Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Red Hat Enterprise Linux 10 Fix deferred freerdp Red Hat Enterprise Linux 6 Out of support scope freerdp Red Hat Enterprise Linux 7 Out of support scope freerdp Red Hat Enterprise Linux 8 Fix deferred freerdp Red Hat Enterprise Linux 9 Fix deferred freerdp https://www.cve.org/CVERecord?id=CVE-2026-67293 https://nvd.nist.gov/vuln/detail/CVE-2026-67293 https://github.com/FreeRDP/FreeRDP/commit/f3b4347105114fe7453828736bea069999af319f https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-5wr6-8m8j-3h7f https://www.vulncheck.com/advisories/freerdp-before-improper-certificate-hostname-validation