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Fencer Vulns
high 8.8

CVE-2026-40033 json

FreeRDP - Heap-buffer-overflow in gdi_CacheToSurface via rectangle validation bypass

published 2026-05-26 5 mo ago modified 2026-11-08 22 h ago also EUVD-2026-31830

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 71%
public exploits
0
none known

Summary

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.

Patch / fix

  • FreeRDP FreeRDP 3.26.0
  • Red Hat Red Hat Enterprise Linux 10 2:3.10.3-12.el10_2.6
  • freerdp3 Debian 14 3.26.0+dfsg-1

debian advisories DEBIAN-CVE-2026-40033

  • freerdp3 Ubuntu 24.04 LTS 3.30.0+dfsg-0ubuntu0.24.04.1
  • freerdp3 Ubuntu 26.04 LTS 3.30.0+dfsg-0ubuntu0.26.04.1

ubuntu advisories UBUNTU-CVE-2026-40033

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • freerdp RHEL 10.2 2:3.10.3-12.el10_2.6
  • libwinpr RHEL 10.2 2:3.10.3-12.el10_2.6
  • freerdp-libs RHEL 10.2 2:3.10.3-12.el10_2.6
  • freerdp-server RHEL 10.2 2:3.10.3-12.el10_2.6
  • freerdp enterprise linux eus 10.0 2:3.10.3-3.el10_0.9
  • libwinpr enterprise linux eus 10.0 2:3.10.3-3.el10_0.9
  • freerdp-libs enterprise linux eus 10.0 2:3.10.3-3.el10_0.9
  • freerdp-server enterprise linux eus 10.0 2:3.10.3-3.el10_0.9

red hat advisories RHSA-2026:46393RHSA-2026:36203

  • freerdp SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7 3.10.3-150700.3.17.1
  • freerdp SLES for SAP applications 16.0, SLES 16.0 3.26.0-160000.1.1

suse advisories SUSE-SU-2026:3562-1SUSE-SU-2026:22194-1

  • freerdp openSUSE Leap 16.0 3.26.0-160000.1.1
  • freerdp openSUSE Tumbleweed 3.26.0-3.1

opensuse advisories openSUSE-SU-2026:21116-1openSUSE-SU-2026:10948-1

  • freerdp AlmaLinux 10 2:3.10.3-12.el10_2.6
  • libwinpr AlmaLinux 10 2:3.10.3-12.el10_2.6
  • freerdp-libs AlmaLinux 10 2:3.10.3-12.el10_2.6
  • freerdp-server AlmaLinux 10 2:3.10.3-12.el10_2.6

almalinux advisories ALSA-2026:36203

  • freerdp Rocky Linux 10 2:3.10.3-12.el10_2.6

rocky linux advisories RLSA-2026:36203

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-40033 updated cvss 8.8

freerdp: FreeRDP: Remote code execution via heap-buffer-overflow in gdi_CacheToSurface

  • Red Hat Enterprise Linux 6 freerdp, freerdp-libs, freerdp-plugins
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 9 freerdp, libwinpr, freerdp-libs
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 10) freerdp 3.10.3-12.el10_2.6, libwinpr 3.10.3-12.el10_2.6, freerdp-libs 3.10.3-12.el10_2.6
    fixed: vendor fix RHSA-2026:36203
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) freerdp 3.10.3-3.el10_0.9, libwinpr 3.10.3-3.el10_0.9, freerdp-libs 3.10.3-3.el10_0.9
    fixed: vendor fix RHSA-2026:46393
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) freerdp-server 3.10.3-12.el10_2.6
    fixed: vendor fix RHSA-2026:36203
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) freerdp-server 3.10.3-3.el10_0.9
    fixed: vendor fix RHSA-2026:46393
  • Red Hat Enterprise Linux 7 freerdp, libwinpr, freerdp-libs, freerdp-plugins Red Hat Enterprise Linux 8 freerdp, libwinpr, freerdp-libs
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
5 mo ago

Exploit prediction

1.36% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.6 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
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CISA ADP 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 4.0 8.7 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

Affected products

  • FreeRDP FreeRDP
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.