FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.28.0, freerdp_dsp_decode_opus in libfreerdp/codec/dsp.c calls Stream_EnsureRemainingCapacity on context->common.buffer even though opus_decode writes decoded PCM into the caller-supplied out stream. A malicious RDP server that negotiates WAVE_FORMAT_OPUS with a client built with WITH_OPUS enabled and WITH_DSP_FFMPEG disabled can make libopus write a large decoded frame beyond the 4096-byte StreamPool_Take destination used by channels/rdpsnd/client/rdpsnd_main.c. This can corrupt the client heap, crash the client, and may permit code execution. This issue is fixed in version 3.28.0.
History

Fri, 21 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-120
References
Metrics threat_severity

None

cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

threat_severity

Important


Wed, 19 Aug 2026 20:00:00 +0000

Type Values Removed Values Added
First Time appeared Freerdp
Freerdp freerdp
Vendors & Products Freerdp
Freerdp freerdp

Wed, 19 Aug 2026 18:15:00 +0000

Type Values Removed Values Added
Description FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.28.0, freerdp_dsp_decode_opus in libfreerdp/codec/dsp.c calls Stream_EnsureRemainingCapacity on context->common.buffer even though opus_decode writes decoded PCM into the caller-supplied out stream. A malicious RDP server that negotiates WAVE_FORMAT_OPUS with a client built with WITH_OPUS enabled and WITH_DSP_FFMPEG disabled can make libopus write a large decoded frame beyond the 4096-byte StreamPool_Take destination used by channels/rdpsnd/client/rdpsnd_main.c. This can corrupt the client heap, crash the client, and may permit code execution. This issue is fixed in version 3.28.0.
Title FreeRDP: Heap buffer overflow in Opus audio decode (`freerdp_dsp_decode_opus` resizes the wrong stream) — server→client
Weaknesses CWE-122
References
Metrics cvssV4_0

{'score': 7.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-21T03:55:50.194Z

Reserved: 2026-07-17T14:11:15.482Z

Link: CVE-2026-63633

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-19T18:17:10.017

Modified: 2026-08-21T04:18:13.663

Link: CVE-2026-63633

cve-icon Redhat

Severity : Important

Publid Date: 2026-08-19T18:00:52Z

Links: CVE-2026-63633 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-21T03:30:09Z