Heap-based buffer overflow in FreeRDP - CVE-2026-63633
Published: July 6, 2026 / Updated: August 21, 2026
Vulnerability identifier: #VU136923
CSH Severity: High
CVSS v4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63633
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to a heap-based buffer overflow in freerdp_dsp_decode_opus in libfreerdp/codec/dsp.c when decoding a server-supplied Opus wave PDU on the rdpsnd audio channel. A remote attacker can send a specially crafted Opus audio packet to execute arbitrary code.
Only clients built with WITH_OPUS enabled and without the FFmpeg DSP backend are vulnerable. User interaction is limited to connecting to the server with audio redirection active.
Affected software
FreeRDP
How to mitigate CVE-2026-63633
Install security update from vendor's website.
FreeRDP - update to 3.28.0