CVE-2026-31883
Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, a size_t underflow in the IMA-ADPCM and MS-ADPCM audio decoders leads to heap-buffer-overflow write via the RDPSND audio channel. In libfreerdp/codec/dsp.c, the IMA-ADPCM and MS-ADPCM decoders subtract block header sizes from a size_t variable without checking for underflow. When nBlockAlign (received from the server) is set such that size % block_size == 0 triggers the header parsing at a point where size is smaller than the header (4 or 8 bytes), the subtraction wraps size to ~SIZE_MAX. The while (size > 0) loop then continues for an astronomical number of iterations. This vulnerability is fixed in 3.24.0.
How to fix CVE-2026-31883
To remediate CVE-2026-31883, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 3.15.0+dfsg-2.1+deb13u2 or later
Is CVE-2026-31883 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0
- from 0, < 3.15.0+dfsg-2.1+deb13u2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |