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.
https://www.vulncheck.com/advisories/freerdp-before-improper-certificate-hostname-validation
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-5wr6-8m8j-3h7f
https://github.com/FreeRDP/FreeRDP/commit/f3b4347105114fe7453828736bea069999af319f
Published: 2026-08-01
Updated: 2026-08-01
Base Score: 4
Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:P/A:N
Severity: Medium
Base Score: 4.2
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Severity: Medium
Base Score: 9.3
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Severity: Critical