# CVE-2026-109939: FreeRDP 3.27.1 before 3.32.0 NULL Pointer Dereference via Cache Bitmap V3 Order

> A malicious RDP server can crash a connecting FreeRDP client by sending a specific order when the non-default Bitmap Cache V3 feature is enabled.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 13 Oct 2026
- **Updated:** 13 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-109939, GHSA-93pr-x2pm-jv23, GHSA-cq4m-gwc5-w8rc, UBUNTU-CVE-2026-109939

## What is CVE-2026-109939?

CVE-2026-109939 is a high-severity vulnerability in Freerdp Freerdp, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

FreeRDP 3.27.1 before 3.32.0 contains a NULL pointer dereference in update_read_cache_bitmap_v3_order() in libfreerdp/core/orders.c, which accesses the client bitmap cache when the CBR3_DO_NOT_CACHE flag is set, even though the cache is not yet initialized before Demand Active. A malicious or compromised RDP server can send a Cache Bitmap V3 order during connection setup to crash a connecting client that has enabled the non-default Bitmap Cache V3 feature (/cache:codec:<rfx|nsc|jpeg>).

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-109939?

It affects 1 product.


Products: Freerdp Freerdp.

## How do I fix CVE-2026-109939?

Upgrade to a fixed version.

## Is CVE-2026-109939 being exploited?

There is no known exploitation of CVE-2026-109939 in the wild and no public exploit code.

## 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-2026-109939 and fix it if it is affected.

What it is: CVE-2026-109939 is a high-severity vulnerability in Freerdp Freerdp, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-109939 in the wild and no public exploit code.

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-2026-109939/ (Markdown: https://insights.sbomify.com/CVE-2026-109939/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-109939
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-109939
- OSV: https://osv.dev/vulnerability/CVE-2026-109939

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-109939/
Summaries are generated and may contain mistakes; the official description above is the record.