CVE-2026-44421

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

HIGH
8.8
CVSS Score
Published: May 29, 2026 at 07:40 PM UTC
Updated: July 27, 2026 at 04:27 PM UTC
1 product affected across 1 vendorFreeRDP

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Severity
HIGH8.8
Exploit prediction
EPSS 0.5%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.26.0
Affected range stops below 3.26.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (6)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/security/cve/CVE-2026-44421
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://bugzilla.redhat.com/show_bug.cgi?id=2483471
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:36203
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:46393

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-122CWE-787

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