# CVE-2026-109246: FreeRDP before 3.32.0 Shadow Server Divide-by-Zero via Frame Acknowledge PDU

> An authenticated client can cause a divide-by-zero crash in the FreeRDP shadow server, disconnecting all viewers.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **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:** 12 Oct 2026
- **Updated:** 18 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-109246, GHSA-6vjv-4hm3-6698, GHSA-jpmc-9q62-wvpv, UBUNTU-CVE-2026-109246

## What is CVE-2026-109246?

CVE-2026-109246 is a high-severity vulnerability in FreeRDP, published on 12 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

FreeRDP before 3.32.0 contains a divide-by-zero vulnerability in the freerdp-shadow-cli shadow server: the frame id in a client's Frame Acknowledge PDU is stored without a range check, so the in-flight frame count in shadow_encoder_inflight_frames() can underflow. An authenticated client can acknowledge a frame id one greater than the last frame sent, causing shadow_encoder_create_frame_id() to divide by zero (SIGFPE) and terminate the process, disconnecting all viewers.

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2026-109246?


## How do I fix CVE-2026-109246?

Upgrade to a fixed version.

## Is CVE-2026-109246 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109246 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-109246 and fix it if it is affected.

What it is: CVE-2026-109246 is a high-severity vulnerability in FreeRDP, published on 12 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109246 exists.

Affected product: 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-2026-109246/ (Markdown: https://insights.sbomify.com/CVE-2026-109246/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-109246
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-109246
- OSV: https://osv.dev/vulnerability/CVE-2026-109246

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-109246/
Summaries are generated and may contain mistakes; the official description above is the record.