# CVE-2026-64621: FreeRDP before 3.28.0 Double-Free via selectedmonitors

> An attacker can trigger a double-free vulnerability in FreeRDP clients by tricking a user into opening a malicious .rdp file, potentially leading to code execution or crashes.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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:** 20 Jul 2026
- **Updated:** 23 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-64621, GHSA-7pv2-4c55-cg52, GHSA-f27x-frr8-j9hc, UBUNTU-CVE-2026-64621

## What is CVE-2026-64621?

CVE-2026-64621 is a critical use after free vulnerability in Freerdp Freerdp, published on 20 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

FreeRDP before 3.28.0 (affected 3.x through 3.27.1) contains a double-free vulnerability in freerdp_client_rdp_file_apply_to_settings() (client/common/file.c) when parsing the selectedmonitors field of a .rdp connection file. The MonitorIds array is allocated through the settings object, and a raw non-owning pointer to it is freed on the strtoul error path without clearing settings->MonitorIds, leaving it dangling; at teardown freerdp_settings_free() frees the same buffer again. An attacker who convinces a victim to open a crafted .rdp file with oversized monitor tokens can trigger a size-controlled double-free in any FreeRDP CLI client (xfreerdp/sdl-freerdp/wlfreerdp) in the default configuration.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2026-64621?

It affects 1 product.


Products: Freerdp Freerdp.

## How do I fix CVE-2026-64621?

Upgrade to a fixed version.

## Is CVE-2026-64621 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-64621 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-2026-64621 and fix it if it is affected.

What it is: CVE-2026-64621 is a critical use after free vulnerability in Freerdp Freerdp, published on 20 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-2026-64621 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-2026-64621/ (Markdown: https://insights.sbomify.com/CVE-2026-64621/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64621
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64621
- OSV: https://osv.dev/vulnerability/CVE-2026-64621

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64621/
Summaries are generated and may contain mistakes; the official description above is the record.