CVE-2026-63117 FreeRDP: Denial of service through ADPCM frame size calculation
An authenticated RDP client can cause a server-side crash via a division by zero in ADPCM frame size calculation, requiring an upgrade to FreeRDP.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-63117?
CVE-2026-63117 is a medium-severity denial of service vulnerability in Freerdp Freerdp, published on 19 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.28.0, an authenticated RDP client can advertise DVI ADPCM with nBlockAlign equal to 8 and nChannels equal to 2 to make the `bs` calculation in rdpsnd_server_select_format in channels/rdpsnd/server/rdpsnd_main.c equal zero. The subsequent out_frames modulo `bs` operation raises SIGFPE and terminates the server-side rdpsnd channel process. This vulnerability fixed in 3.28.0.
Weakness: CWE-369
Which versions are affected by CVE-2026-63117?
It affects 1 product.
Products include Freerdp Freerdp.
How do I fix CVE-2026-63117?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-63117 being exploited?
There is no known exploitation of CVE-2026-63117 in the wild and no public exploit code.
Other vulnerabilities in Freerdp Freerdp
- CVE-2021-37594 Other in n/a
- CVE-2021-37595 Other in n/a
- CVE-2026-67305 FreeRDP Windows Client before 3.29.0 Heap Buffer Overflow via Cliprdr
- CVE-2026-66402 FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass
- CVE-2026-67289 FreeRDP before 3.29.0 HTTP Proxy Request Injection via Redirection
Sources
Also known as DEBIAN-CVE-2026-63117, GHSA-v64m-xxfw-hrv6, UBUNTU-CVE-2026-63117.