High [CVE-2026-63633] Arbitrary code execution via heap buffer overflow in Opus audio decode
This high-severity Red Hat Linux advisory covers CVE-2026-63633 affecting Red Hat Enterprise Linux 10, Red Hat package: freerdp.
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Summary
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. A malicious Remote Desktop Protocol (RDP) server can exploit a heap buffer overflow vulnerability during Opus audio decoding.
This occurs when the server negotiates Opus audio with a vulnerable client, causing the client to write data beyond an allocated memory buffer. This can lead to client crashes, memory corruption, and potentially allow the malicious server to execute arbitrary code on the client system.
A heap buffer overflow vulnerability was found in FreeRDP's DSP audio codec module (`libfreerdp/codec/dsp.c`). When built with `WITH_OPUS` and without `WITH_DSP_FFMPEG`, `freerdp_dsp_decode_opus` fails to validate destination buffer capacity when handling `WAVE_FORMAT_OPUS` streams.
- < 3.28.0
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- To mitigate this vulnerability, disable audio redirection on client connections by omitting audio parameters (such as `/sound` or `/audio`) in `xfreerdp` to bypass client-side DSP audio decoding.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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