# CVE-2026-67298: FreeRDP 3.28.0 Heap Buffer Overflow via RAIL orderLength Underflow

> A malicious RDP client can trigger a heap buffer overflow in FreeRDP server via integer underflow, causing crashes or potential code execution.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/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:** Not needed
- **Fix available:** Yes
- **Published:** 1 Aug 2026
- **Updated:** 3 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-67298, GHSA-wrfm-6x9r-42cr, UBUNTU-CVE-2026-67298

## What is CVE-2026-67298?

CVE-2026-67298 is a high-severity vulnerability in FreeRDP, published on 1 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

FreeRDP versions 3.28.0 and earlier contain a heap buffer overflow in the server-side RAIL channel handler (rail_server_handle_messages() in channels/rail/server/rail_main.c). When processing a RAIL PDU header, the code subtracts RAIL_PDU_HEADER_LENGTH from the peer-controlled orderLength field without first verifying orderLength is at least the header length. For orderLength values 0..3 this causes an unsigned integer underflow to a very large size, which bypasses the Stream_EnsureRemainingCapacity() capacity check (due to pointer arithmetic wraparound) and is then passed to WTSVirtualChannelRead(), resulting in an out-of-bounds heap write. A malicious or compromised RDP client can exploit this to corrupt the heap and crash the server. Fixed in FreeRDP 3.29.0.

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2026-67298?


## How do I fix CVE-2026-67298?

Upgrade to a fixed version.

## Is CVE-2026-67298 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67298 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-67298 and fix it if it is affected.

What it is: CVE-2026-67298 is a high-severity vulnerability in FreeRDP, published on 1 Aug 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-2026-67298 exists.

Affected product: 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-2026-67298/ (Markdown: https://insights.sbomify.com/CVE-2026-67298/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-67298
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-67298
- OSV: https://osv.dev/vulnerability/CVE-2026-67298

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-67298/
Summaries are generated and may contain mistakes; the official description above is the record.