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CVE-2026-31806— FreeRDP has a Heap Buffer Overflow in nsc_process_message() via Unchecked SURFACE_BITS_COMMAND Bitmap Dimensions

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 3.24.0之前版本存在安全漏洞，该漏洞源于gdi_surface_bits函数未正确验证服务器提供的bmp.width和bmp.height值，可能导致堆缓冲区溢出。

AI Predicted 8.8 Difficulty: Moderate EPSS 0.66% · P48

Affected Version Matrix 1

VendorProduct Version RangeStatus
FreeRDP FreeRDP < 3.24.0 affected
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I. Basic Information for CVE-2026-31806

Vulnerability Information
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Vulnerability Title
FreeRDP has a Heap Buffer Overflow in nsc_process_message() via Unchecked SURFACE_BITS_COMMAND Bitmap Dimensions
Source: CVE Program / CVE List V5
Vulnerability Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, the gdi_surface_bits() function processes SURFACE_BITS_COMMAND messages sent by the RDP server. When the command is handled using NSCodec, the bmp.width and bmp.height values provided by the server are not properly validated against the actual desktop dimensions. A malicious RDP server can supply crafted bmp.width and bmp.height values that exceed the expected surface size. Because these values are used during bitmap decoding and memory operations without proper bounds checking, this can lead to a heap buffer overflow. Since the attacker can also control the associated pixel data transmitted by the server, the overflow may be exploitable to overwrite adjacent heap memory. This vulnerability is fixed in 3.24.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
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 3.24.0之前版本存在安全漏洞，该漏洞源于gdi_surface_bits函数未正确验证服务器提供的bmp.width和bmp.height值，可能导致堆缓冲区溢出。
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 < 3.24.0 -

II. Public POCs for CVE-2026-31806

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III. Intelligence Information for CVE-2026-31806

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Patches & Fixes for CVE-2026-31806 (1)

Vendor Advisories for CVE-2026-31806 (1)

Same Patch Batch · FreeRDP · 2026-03-13 · 8 CVEs total

CVE-2026-31883 6.5 MEDIUM FreeRDP has a `size_t` underflow in ADPCM decoder leads to heap-buffer-overflow write
CVE-2026-31884 6.5 MEDIUM FreeRDP has a division-by-zero in ADPCM decoders when `nBlockAlign` is 0
CVE-2026-31885 6.5 MEDIUM FreeRDP has an out-of-bounds read in ADPCM decoders due to missing predictor/step_index bo
CVE-2026-29775 5.3 MEDIUM FreeRDP has a heap-buffer-overflow in bitmap_cache_put via OOB cacheId
CVE-2026-29774 5.3 MEDIUM FreeRDP has a heap-buffer-overflow in avc420_yuv_to_rgb via OOB regionRects
CVE-2026-29776 3.1 LOW FreeRDP has an Integer Underflow in update_read_cache_bitmap_order Function of FreeRDP's C
CVE-2026-31897 FreeRDP has an out-of-bounds read in `freerdp_bitmap_decompress_planar`

IV. Related Vulnerabilities

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

V. Comments for CVE-2026-31806

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