# CVE-2026-91947: FreeRDP Server before 3.31.0 Use-After-Free via DRDYNVC

> Authenticated clients can trigger a use-after-free in FreeRDP server via race conditions, potentially leading to code execution or denial of service.

- **Severity:** High 7.7 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/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:** 15 Sep 2026
- **Updated:** 16 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-91947, GHSA-6mpx-c8rj-whj5, GHSA-chpg-x28q-pmrg, UBUNTU-CVE-2026-91947

## What is CVE-2026-91947?

CVE-2026-91947 is a high-severity use after free vulnerability in FreeRDP, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

FreeRDP server versions before 3.31.0 contain a use-after-free vulnerability in the DRDYNVC parser that dereferences a channel pointer after releasing the synchronization lock. Authenticated clients can race AUDIN channel closure messages against DRDYNVC data parsing to trigger heap-use-after-free when accessing freed channel objects.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-91947?


## How do I fix CVE-2026-91947?

Upgrade to a fixed version.

## Is CVE-2026-91947 being exploited?

There is no known exploitation of CVE-2026-91947 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-91947 and fix it if it is affected.

What it is: CVE-2026-91947 is a high-severity use after free vulnerability in FreeRDP, published on 15 Sep 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-2026-91947 in the wild and no public exploit code.

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-2026-91947/ (Markdown: https://insights.sbomify.com/CVE-2026-91947/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-91947
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-91947
- OSV: https://osv.dev/vulnerability/CVE-2026-91947

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-91947/
Summaries are generated and may contain mistakes; the official description above is the record.