Paper/Archive/CVE-2026-63633

CVE-2026-63633

FreeRDP FreeRDP — FreeRDP: Heap buffer overflow in Opus audio decode (`freerdp_dsp_decode_opus` resizes the wrong stream) — server→client

EPSS 0.6%public exploit CVSS 9.8

critical.is priorityof 100

CVSS 9.8 (NVD)9.8 / 10 × 3029.4 Not in CISA KEV+300.0 EPSS percentile 49.6.496 × 209.9 Exploit: SSVC poc+1010.0 SSVC exploitation: poc+100.0

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource

FreeRDP< 3.28.0–CNA

Scores by source

NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

GitHub_M (CNA)7.7CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CISA ADPSSVCExploitation: poc · Automatable: no · Technical impact: total

References

refgithub.com/FreeRDP/FreeRDP/security/advisories/GHSA-72j9-356v-88xq refgithub.com/FreeRDP/FreeRDP/pull/12993 refgithub.com/FreeRDP/FreeRDP/commit/0ed1f95d36913581cf31124f94eb5843d4263eae refgithub.com/FreeRDP/FreeRDP/releases/tag/3.28.0