CVE-2026-40033 HIGH

CVE-2026-40033: FreeRDP - Heap-buffer-overflow in gdi_CacheToSurface via rectangle validation bypass

Vendor Freerdp
Product FreeRDP
Weakness CWE-122
Published May 26, 2026
Last update June 30, 2026

CVSS base score

8.6/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

What the vulnerability does

01Description

FreeRDP before 3.26.0 contains a heap-buffer-overflow vulnerability in gdi_CacheToSurface that allows remote attackers to write out-of-bounds heap memory. The vulnerability occurs because rectangle validation clamps coordinates to UINT16_MAX but performs copy operations using unclamped cache entry dimensions, enabling malicious RDP servers to trigger large out-of-bounds writes and potentially achieve remote code execution or client crash.

Key dates

02Disclosure timeline

May 26, 2026 CVE published
June 30, 2026 Record updated