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CVE-2026-44421— FreeRDP RDPGFX CacheToSurface heap-buffer-overflow via clamped-rectangle validation bypass

Quick assessment

Affected
FreeRDP FreeRDP
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

FreeRDP是FreeRDP团队的一款开源的远程桌面协议（RDP）的实现。 FreeRDP 3.26.0之前版本存在安全漏洞，该漏洞源于恶意RDP服务器可通过发送特制RDPGFX PDU触发客户端堆缓冲区溢出写入，gdi_CacheToSurface中验证目标矩形但使用原始cacheEntry->width/height进行复制，可能导致客户端崩溃或代码执行。

CVSS 8.8 · High EPSS 0.72% · P52

Affected Version Matrix 1

VendorProduct Version RangeStatus
FreeRDP FreeRDP < 3.26.0 affected
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I. Basic Information for CVE-2026-44421

Vulnerability Information
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Vulnerability Title
FreeRDP RDPGFX CacheToSurface heap-buffer-overflow via clamped-rectangle validation bypass
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
堆缓冲区溢出
Source: CVE Program / CVE List V5
Vulnerability Title
FreeRDP 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
FreeRDP是FreeRDP团队的一款开源的远程桌面协议（RDP）的实现。 FreeRDP 3.26.0之前版本存在安全漏洞，该漏洞源于恶意RDP服务器可通过发送特制RDPGFX PDU触发客户端堆缓冲区溢出写入，gdi_CacheToSurface中验证目标矩形但使用原始cacheEntry->width/height进行复制，可能导致客户端崩溃或代码执行。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
FreeRDP FreeRDP < 3.26.0 -

II. Public POCs for CVE-2026-44421

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 12877 chars
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Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
In-depth vulnerability mechanism
Trigger conditions & impact
Full executable POC code
Exploit chain & mitigation
POC zip download
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III. Intelligence Information for CVE-2026-44421

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Vendor Advisories for CVE-2026-44421 (1)

Same Patch Batch · FreeRDP · 2026-05-29 · 4 CVEs total

CVE-2026-44420 8.8 HIGH FreeRDP cliprdr server heap-buffer-overflow via undersized capabilitySetLength in CB_CLIP_
CVE-2026-45700 7.7 HIGH Heap-buffer-overflow write in planar bitmap decoder
CVE-2026-44422 7.5 HIGH FreeRDP RDPEAR NDR ref-id aliasing causes client-side UAF/double-free and type confusion

IV. Related Vulnerabilities

Same product: FreeRDP
Same vendor: FreeRDP
Same weakness: CWE-122

V. Comments for CVE-2026-44421

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