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CVE-2026-23531— FreeRDP has heap-buffer-overflow in clear_decompress

Quick assessment

Affected
FreeRDP FreeRDP
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
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 3.21.0之前版本存在安全漏洞，该漏洞源于ClearCodec中的clear_decompress函数未验证目标矩形，可能导致越界读写，进而引发堆缓冲区溢出，造成崩溃或任意代码执行。

AI Predicted 7.8 Difficulty: Moderate EPSS 0.52% · P42

Affected Version Matrix 1

VendorProduct Version RangeStatus
FreeRDP FreeRDP < 3.21.0 affected
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I. Basic Information for CVE-2026-23531

Vulnerability Information
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Vulnerability Title
FreeRDP has heap-buffer-overflow in clear_decompress
Source: CVE Program / CVE List V5
Vulnerability Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, in ClearCodec, when `glyphData` is present, `clear_decompress` calls `freerdp_image_copy_no_overlap` without validating the destination rectangle, allowing an out-of-bounds read/write via crafted RDPGFX surface updates. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P
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 3.21.0之前版本存在安全漏洞，该漏洞源于ClearCodec中的clear_decompress函数未验证目标矩形，可能导致越界读写，进而引发堆缓冲区溢出，造成崩溃或任意代码执行。
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 < 3.21.0 -

II. Public POCs for CVE-2026-23531

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III. Intelligence Information for CVE-2026-23531

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Patches & Fixes for CVE-2026-23531 (1)

Same Patch Batch · FreeRDP · 2026-01-19 · 8 CVEs total

CVE-2026-23884 Heap-use-after-free in gdi_set_bounds
CVE-2026-23883 Heap-use-after-free in update_pointer_new
CVE-2026-23732 FreeRDP has heap-buffer-overflow in Glyph_Alloc
CVE-2026-23534 FreeRDP has heap-buffer-overflow in clear_decompress_bands_data
CVE-2026-23533 FreeRDP has heap-buffer-overflow in clear_decompress_residual_data
CVE-2026-23532 FreeRDP has heap-buffer-overflow in gdi_SurfaceToSurface
CVE-2026-23530 FreeRDP has heap-buffer-overflow in planar_decompress_plane_rle

IV. Related Vulnerabilities

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

V. Comments for CVE-2026-23531

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