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CVE-2026-31883

FreeRDP has a `size_t` underflow in ADPCM decoder leads to heap-buffer-overflow write

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 3.24.0
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: poc
  • Automatable: yes
  • Technical impact: partial

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • FreeRDP FreeRDP

    fixed in 3.24.0

References 2

GitHub · FreeRDP/FreeRDP