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CVE-2026-31884— FreeRDP has a division-by-zero in ADPCM decoders when `nBlockAlign` is 0

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之前版本存在数字错误漏洞，该漏洞源于当nBlockAlign为0时，MS-ADPCM和IMA-ADPCM解码器中存在除零错误，可能导致崩溃。

CVSS 6.5 · Medium EPSS 0.30% · P21

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service
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I. Basic Information for CVE-2026-31884

Vulnerability Information
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Vulnerability Title
FreeRDP has a division-by-zero in ADPCM decoders when `nBlockAlign` is 0
Source: CVE Program / CVE List V5
Vulnerability Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, division by zero in MS-ADPCM and IMA-ADPCM decoders when nBlockAlign is 0, leading to a crash. In libfreerdp/codec/dsp.c, both ADPCM decoders use size % block_size where block_size = context->common.format.nBlockAlign. The nBlockAlign value comes from the Server Audio Formats PDU on the RDPSND channel. The value 0 is not validated anywhere before reaching the decoder. When nBlockAlign = 0, the modulo operation causes a SIGFPE (floating point exception) crash. This vulnerability is fixed in 3.24.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
除零错误
Source: CVE Program / CVE List V5
Vulnerability Title
FreeRDP 数字错误漏洞
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之前版本存在数字错误漏洞，该漏洞源于当nBlockAlign为0时，MS-ADPCM和IMA-ADPCM解码器中存在除零错误，可能导致崩溃。
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-2026-31884

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III. Intelligence Information for CVE-2026-31884

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Patches & Fixes for CVE-2026-31884 (2)

Vendor Advisories for CVE-2026-31884 (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-2026-31885 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`
CVE-2026-31806 FreeRDP has a Heap Buffer Overflow in nsc_process_message() via Unchecked SURFACE_BITS_COM

IV. Related Vulnerabilities

Same product: FreeRDP
Same vendor: FreeRDP
Same weakness: CWE-369

V. Comments for CVE-2026-31884

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