# 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.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-63117, GHSA-v64m-xxfw-hrv6, UBUNTU-CVE-2026-63117

## 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 (Divide By Zero)

## Which versions are affected by CVE-2026-63117?

It affects 1 product.


Products: Freerdp Freerdp.

## How do I fix CVE-2026-63117?

Upgrade to a fixed version.

## 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](https://insights.sbomify.com/CVE-2021-37594/): Other in n/a (critical 9.8)
- [CVE-2021-37595](https://insights.sbomify.com/CVE-2021-37595/): Other in n/a (critical 9.8)
- [CVE-2026-67305](https://insights.sbomify.com/CVE-2026-67305/): FreeRDP Windows Client before 3.29.0 Heap Buffer Overflow via Cliprdr (critical 9.4)
- [CVE-2026-66402](https://insights.sbomify.com/CVE-2026-66402/): FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass (critical 9.3)
- [CVE-2026-67289](https://insights.sbomify.com/CVE-2026-67289/): FreeRDP before 3.29.0 HTTP Proxy Request Injection via Redirection (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63117 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-63117 in the wild and no public exploit code.

Affected product: Freerdp Freerdp. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-63117/ (Markdown: https://insights.sbomify.com/CVE-2026-63117/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63117
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63117
- OSV: https://osv.dev/vulnerability/CVE-2026-63117

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63117/
Summaries are generated and may contain mistakes; the official description above is the record.