CVE-2026-31884

FreeRDP has a division-by-zero in ADPCM decoders when `nBlockAlign` is 0

CVSS 6.5 MEDIUMEPSS 0.3%CWE-369

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 6.5EPSS 0.3%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

13 Mar 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected products

FreeRDP · FreeRDP

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References

https://github.com/FreeRDP/FreeRDP/commit/03b48b3601d867afccac1cdc6081de7a275edce7 https://github.com/FreeRDP/FreeRDP/commit/16df2300e1e3f5a51f68fb1626429e58b531b7c8 https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-jp7m-94ww-p56r