CVE-2026-44421

HIGH

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

Title source: cna
STIX 2.1

Description

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.

References (1)

Core 1
Core References

Scores

CVSS v3 8.8
EPSS 0.0030
EPSS Percentile 21.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact total

Details

CWE
CWE-122
Status published
Products (2)
freerdp/freerdp < 3.26.0
FreeRDP/FreeRDP < 3.26.0
Published May 29, 2026
Tracked Since May 30, 2026