# CVE-2026-63652: FreeRDP: Double-free of `client_formats` in the rdpsnd server channel on a malformed Client Audio Formats PDU

> An authenticated RDP client can trigger a double-free in FreeRDP's audio channel, causing server termination or potential heap corruption.

- **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:** 19 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-63652, GHSA-9g22-w2gr-vcmp, UBUNTU-CVE-2026-63652

## What is CVE-2026-63652?

CVE-2026-63652 is a high-severity use after free 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, rdpsnd_server_recv_formats in channels/rdpsnd/server/rdpsnd_main.c frees context->client_formats on a malformed Client Audio Formats PDU without clearing the owning pointer or num_client_formats. An authenticated RDP client can trigger an error such as a cbSize larger than the remaining record, leave the dangling pointer in the server context, and cause rdpsnd_server_context_free to free the same allocation again at session teardown. This reliably terminates the server and can create allocator-dependent heap corruption. This issue is fixed in version 3.28.0.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2026-63652?

It affects 1 product.


Products: Freerdp Freerdp.

## How do I fix CVE-2026-63652?

Upgrade to a fixed version.

## Is CVE-2026-63652 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63652 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-2026-63652 and fix it if it is affected.

What it is: CVE-2026-63652 is a high-severity use after free 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63652 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-2026-63652/ (Markdown: https://insights.sbomify.com/CVE-2026-63652/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63652
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63652
- OSV: https://osv.dev/vulnerability/CVE-2026-63652

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63652/
Summaries are generated and may contain mistakes; the official description above is the record.