CVE-2026-63633

Critical

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.

SeverityCritical
CVSS9.8
Exploit probability—
ProductFreerdp
PublishedAug 19, 2026
First seenAug 19, 2026
Weakness typeCWE-122CWE-122

How to fix

Update
  • freerdp freerdp3.28.0 or later

Affected products

ProductAffected versionsFixed in
freerdp freerdpv < 3.28.03.28.0

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