CVE-2026-66402

Public on 2026-08-01
Modified on 2026-08-01
Description
FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains multiple TLS certificate identity validation weaknesses in tls_verify_certificate(), tls_match_hostname(), and x509_utils_get_dns_names(). Because FreeRDP performs custom Common Name and DNS SAN string matching instead of using OpenSSL's length-aware identity validation APIs, it (1) truncates DNS SAN values at embedded NUL bytes (accepting e.g. 'victim.example\0.attacker.example' as 'victim.example'), (2) accepts a matching Common Name even when non-matching DNS SAN entries are present, and (3) accepts IP-literal targets via DNS/CN matching without comparing iPAddress SANs. Under a trusted or misissued certificate chain, an attacker positioned to present such a certificate can bypass server identity verification, weakening TLS server authentication.
Severity
Important severity
Important
See what this means
CVSS v3 Base Score
7.4
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 2 - Core freerdp Pending Fix
Amazon Linux 2023 freerdp Pending Fix

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N