Improper Certificate Validation Vulnerability in FreeRDP by FreeRDP
CVE-2026-121392

9.1CRITICAL

Key Information:

Vendor

Freerdp

Status
Freerdp
Vendor
CVE Published:
3 November 2026

What is CVE-2026-121392?

FreeRDP prior to version 3.32.2 has a vulnerability in the tls_verify_certificate() function, which improperly validates certificates. Specifically, it allows a fallback of the Common Name even when the Subject Alternative Name (SAN) entries do not match, and it can erroneously match IP literals against DNS strings. This weakness enables man-in-the-middle attackers, possessing a certificate from a CA trusted by the client, to bypass crucial server identity verification checks. This exploitation permits the interception of remote desktop protocol (RDP) sessions, exposing sensitive information such as keystrokes, clipboard data, and screen output to unauthorized observers.

Affected Version(s)

FreeRDP 0 < 3.32.2

FreeRDP 3.32.2

References

https://github.com/FreeRDP/FreeRDP/security/advisories/GH...
vendor-advisory
https://www.vulncheck.com/advisories/freerdp-before-3.32....
third-party-advisory

CVSS V4

Score:
9.1
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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