# CVE-2026-33516: xrdp: Pre-authentication out-of-bounds reads in RDP capability and channel parsers

> Remote unauthenticated attackers can cause crashes or read sensitive memory via crafted RDP packets in xrdp.

- **Severity:** High 7.7 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 17 Apr 2026
- **Updated:** 20 Apr 2026
- **Also known as:** DEBIAN-CVE-2026-33516, GHSA-rvh9-9wm3-28c7, UBUNTU-CVE-2026-33516

## What is CVE-2026-33516?

CVE-2026-33516 is a high-severity vulnerability in neutrinolabs xrdp, published on 17 Apr 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

xrdp is an open source RDP server. Versions through 0.10.5 contain an out-of-bounds read vulnerability during the RDP capability exchange phase. The issue occurs when memory is accessed before validating the remaining buffer length. A remote, unauthenticated attacker can trigger this vulnerability by sending a specially crafted Confirm Active PDU. Successful exploitation could lead to a denial of service (process crash) or potential disclosure of sensitive information from the process memory. This issue has been fixed in version 0.10.6.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-33516?

It affects 1 product.


Products: Neutrinolabs Xrdp.

## How do I fix CVE-2026-33516?

Upgrade to a fixed version.

## Is CVE-2026-33516 being exploited?

There is no known exploitation of CVE-2026-33516 in the wild and no public exploit code.

## Other vulnerabilities in neutrinolabs xrdp

- [CVE-2026-41252](https://insights.sbomify.com/CVE-2026-41252/): xrdp: lib_palette_update Heap Buffer Overflow & RCE (critical 9.8)
- [CVE-2026-32105](https://insights.sbomify.com/CVE-2026-32105/): xrdp: RDP MAC signature (dataSignature) never verified on receive — integrity bypass in non-TLS mode (critical 9.3)
- [CVE-2026-44178](https://insights.sbomify.com/CVE-2026-44178/): xrdp: Channel Data Forwarding Fixed-Size Buffer Overflow (high 8.8)
- [CVE-2026-32107](https://insights.sbomify.com/CVE-2026-32107/): xrdp: Fail-open privilege drop in sesexec — child processes may execute as root if setuid fails (high 8.8)
- [CVE-2026-33689](https://insights.sbomify.com/CVE-2026-33689/): xrdp: Pre-authentication out-of-bounds reads in channel parsers (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-33516 and fix it if it is affected.

What it is: CVE-2026-33516 is a high-severity vulnerability in neutrinolabs xrdp, published on 17 Apr 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-2026-33516 in the wild and no public exploit code.

Affected product: neutrinolabs xrdp. 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-2026-33516/ (Markdown: https://insights.sbomify.com/CVE-2026-33516/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33516
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33516
- OSV: https://osv.dev/vulnerability/CVE-2026-33516

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33516/
Summaries are generated and may contain mistakes; the official description above is the record.