Freerdp · Freerdp · CVE-2026-31884
**Name of the Vulnerable Software and Affected Versions**
FreeRDP versions prior to 3.24.0
**Description**
FreeRDP is a free implementation of the Remote Desktop Protocol. A division by zero error exists in the MS-ADPCM and IMA-ADPCM decoders when the `nBlockAlign` variable is 0, resulting in a crash. The issue occurs in `libfreerdp/codec/dsp.c` where the decoders use `size % block size`, with `block size` equal to `context->common.format.nBlockAlign`. The `nBlockAlign` value originates from the Server Audio Formats PDU on the RDPSND channel and is not validated before being used in the decoder. When `nBlockAlign` is 0, a SIGFPE (floating point exception) crash occurs.
**Recommendations**
Versions prior to 3.24.0 should be updated to version 3.24.0 or later.