Description
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.
Affected products
freerdp: freerdp
References10
- github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m… ExploitMitigationVendor Advisory
- github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m… ExploitMitigationVendor Advisory
- github.com/FreeRDP/FreeRDP/commit/d7508ebcd82842a691ae4941e5104…
- github.com/FreeRDP/FreeRDP/pull/12713
- www.vulncheck.com/advisories/freerdp-heap-buffer-overflow-in-gd… Third Party Advisory
- access.redhat.com/errata/RHSA-2026:36203
- access.redhat.com/errata/RHSA-2026:46393
- access.redhat.com/security/cve/CVE-2026-40033
- bugzilla.redhat.com/show_bug.cgi?id=2481473
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40033…
Metrics
- CVSS 3.1
-
8.8
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - CVSS 4.0
-
8.7
HIGH
Score source: CNA
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 - EPSS — exploit probability
- 1% percentile: 72 · as of 14 November 2026
- CWE
- CWE-122CWE-787
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.