# CVE-2026-56297: FreeRDP - Use-After-Free via Race Condition in DRDYNVC Channel Callback

> A malicious RDP server can trigger a race condition in FreeRDP leading to use-after-free, potentially enabling remote code execution or denial of service.

- **Severity:** High 8.3 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Jul 2026
- **Updated:** 8 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-56297, GHSA-392f-f2j5-97qm, GHSA-3mv2-5q57-2v8h, UBUNTU-CVE-2026-56297

## What is CVE-2026-56297?

CVE-2026-56297 is a high-severity use after free vulnerability in Freerdp Freerdp, published on 8 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

FreeRDP before 3.22.0 contains a use-after-free vulnerability in dvcman_channel_close and dvcman_call_on_receive due to improper synchronization of channel_callback access. A malicious RDP server can trigger a race condition by sending DYNVC_DATA and DYNVC_CLOSE messages concurrently, causing heap-use-after-free in the drdynvc client thread and potentially enabling remote code execution or denial of service.

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

## Which versions are affected by CVE-2026-56297?

It affects 1 product.


Products: Freerdp Freerdp.

## How do I fix CVE-2026-56297?

Upgrade to a fixed version.

## Is CVE-2026-56297 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56297 exists.

## 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-2026-56297 and fix it if it is affected.

What it is: CVE-2026-56297 is a high-severity use after free vulnerability in Freerdp Freerdp, published on 8 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56297 exists.

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-2026-56297/ (Markdown: https://insights.sbomify.com/CVE-2026-56297/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56297
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56297
- OSV: https://osv.dev/vulnerability/CVE-2026-56297

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-56297/
Summaries are generated and may contain mistakes; the official description above is the record.