Review reviewHigh

CVE-2026-40033

FreeRDP FreeRDP, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6

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: 8.7
EPSS: 1.04%
CISA KEV: Not listed
Published: 2026.05.27

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability1.04%

Technical severityCVSS 8.7

Vulnerability overview

Affected product and versions

Product: FreeRDP FreeRDP, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6
Affected versions: < 3.26.0
Fixed versions: 3.26.0

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that FreeRDP FreeRDP, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

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/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
CWE: CWE-122, CWE-787