CVE-2026-44421CWE-122

FreeRDP RDPGFX CacheToSurface heap-buffer-overflow via clamped-rectangle validation bypass

High · published May 29, 2026

CVSS v3.1
8.8
EPSS
1%
Percentile
53.3
In the wild
Unconfirmed
What it is

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, a malicious RDP server can trigger a heap-buffer-overflow write in the FreeRDP client by sending crafted RDPGFX PDUs. The bug is in gdi_CacheToSurface: it validates a destination rectangle that is clamped to UINT16_MAX, but then performs the copy using the original cacheEntry->width/height. This can cause a large out-of-bounds heap write and may lead to client crashes or code execution. This bug is reachable from a malicious RDP server, but only when the client has RDPGFX enabled. This vulnerability is fixed in 3.26.0.

The record
Technical detail
CVSS v3.1
8.8 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00717 · 53.3th percentile
Weakness
CWE-122 · Heap-based Buffer Overflow
Published
2026-05-29T19:40Z
EPSS history
Timeline
  • 29 MAY 19:40Z
    FreeRDP RDPGFX CacheToSurface heap-buffer-overflow via clamped-rectangle validation bypass
    cvelistv5