FreeRDP up to 3.27.x DSP Codec libfreerdp/codec/dsp.c freerdp_dsp_decode_opus heap-based overflow

Summaryinfo

A vulnerability was found in FreeRDP up to 3.27.x. It has been classified as critical. The impacted element is the function freerdp_dsp_decode_opus of the file libfreerdp/codec/dsp.c of the component DSP Codec. Performing a manipulation results in heap-based overflow. This vulnerability is cataloged as CVE-2026-63633. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in FreeRDP up to 3.27.x. It has been classified as critical. This affects the function freerdp_dsp_decode_opus of the file libfreerdp/codec/dsp.c of the component DSP Codec. The manipulation with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-63633 since 07/17/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 3.28.0 eliminates this vulnerability.

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Productinfo

Type

• Remote Access Software

Name

• FreeRDP

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12
• 3.13
• 3.14
• 3.15
• 3.16
• 3.17
• 3.18
• 3.19
• 3.20
• 3.21
• 3.22
• 3.23
• 3.24
• 3.25
• 3.26
• 3.27

License

• open-source

Website

• Product: https://github.com/FreeRDP/FreeRDP/

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