Name: CVE-2026-40033: Heap-based Buffer Overflow
Creator: Rapid7
Published: 2026-05-26T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-40033, CWE-787, CWE-122, CVSS 8.8, EPSS 0.00808

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.

CVSS Details

CVSS 4.0 Base Score: 8.7 (HIGH)
CVSS 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
CVSS 3.1 Base Score: 8.8
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Amazon Linux Ami 2	—	Upgrade libwinprUpgrade freerdp-develUpgrade freerdpUpgrade libwinpr-develUpgrade freerdp-libsUpgrade freerdp-debuginfo	Jun 23, 2026	Jun 23, 2026
Amazon_linux_2023	—	Upgrade freerdp-server-debuginfoUpgrade libwinpr-debuginfoUpgrade libwinprUpgrade freerdp-libs-debuginfoUpgrade freerdp-develUpgrade freerdp-libsUpgrade freerdp-serverUpgrade freerdp-debugsourceUpgrade freerdpUpgrade freerdp-debuginfoUpgrade libwinpr-devel	Jun 23, 2026	May 26, 2026
Oracle_linux	—	Upgrade freerdpUpgrade freerdp-develUpgrade libwinpr-develUpgrade freerdp-libsUpgrade libwinprUpgrade freerdp-server	Oct 22, 2026	May 26, 2026
Redhat_linux	—	No solution existsUpgrade freerdp-libs-debuginfoUpgrade freerdp-debugsourceUpgrade freerdp-libsUpgrade freerdp-debuginfoUpgrade freerdp-serverUpgrade libwinpr-debuginfoUpgrade libwinpr-develUpgrade freerdp-develUpgrade libwinprUpgrade freerdpUpgrade freerdp-server-debuginfo	Jul 9, 2026	May 26, 2026
Rocky_linux	—	Upgrade freerdp-server-debuginfoUpgrade freerdp-libsUpgrade freerdp-debugsourceUpgrade freerdp-libs-debuginfoUpgrade freerdp-develUpgrade freerdp-serverUpgrade libwinprUpgrade libwinpr-debuginfoUpgrade libwinpr-develUpgrade freerdp-debuginfoUpgrade freerdp	Jul 10, 2026	Jul 8, 2026
Ubuntu	—	Upgrade libfreerdp3-3Upgrade freerdp-x11Upgrade freerdp3-x11	Jul 21, 2026	Jul 20, 2026

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CVSS Details

Covered by Rapid7

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