# CVE-2026-25959: FreeRDP has heap-use-after-free in xf_cliprdr_provide_data_

> A race condition in FreeRDP's clipboard handling allows attackers to trigger a heap use-after-free, potentially leading to code execution or crashes.

- **Severity:** Medium 5.5 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Feb 2026
- **Updated:** 26 Feb 2026
- **Also known as:** DEBIAN-CVE-2026-25959, GHSA-78xg-v4p2-4w3c, MINI-rrvv-42rg-fghx, UBUNTU-CVE-2026-25959

## What is CVE-2026-25959?

CVE-2026-25959 is a medium-severity use after free vulnerability in Freerdp Freerdp, published on 25 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, `xf_cliprdr_provide_data_` passes freed `pDstData` to `XChangeProperty` because the cliprdr channel thread calls `xf_cliprdr_server_format_data_response` which converts and uses the clipboard data without holding any lock, while the X11 event thread concurrently calls `xf_cliprdr_clear_cached_data` → `HashTable_Clear` which frees the same data via `xf_cached_data_free`, triggering a heap use after free. Version 3.23.0 fixes the issue.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-25959?

It affects 1 product.


Products: Freerdp Freerdp.

## How do I fix CVE-2026-25959?

Upgrade to a fixed version.

## Is CVE-2026-25959 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-25959 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-2026-25959 and fix it if it is affected.

What it is: CVE-2026-25959 is a medium-severity use after free vulnerability in Freerdp Freerdp, published on 25 Feb 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-2026-25959 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-2026-25959/ (Markdown: https://insights.sbomify.com/CVE-2026-25959/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25959
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25959
- OSV: https://osv.dev/vulnerability/CVE-2026-25959

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25959/
Summaries are generated and may contain mistakes; the official description above is the record.