---
id: "CVE-2026-121951"
kind: "vulnerability"
aliases: ["CVE-2026-121951"]
title: "FreeRDP: malformed RDP input event crashes server, causing denial of service"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["freerdp", "linux", "package", "rdp-server", "windows"]
not_affected_if: ["client-only", "default-release-build", "no-rdp-server"]
published_at: "2026-11-04T16:17:47+00:00"
first_seen_at: "2026-11-04T16:28:11+00:00"
updated_at: "2026-11-04T16:28:45+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121951", "first_seen_at": "2026-11-04T16:28:11+00:00"}]
---

# FreeRDP: malformed RDP input event crashes server, causing denial of service

FreeRDP's server-side input parser skips a six-byte body on unknown slow-path input events without checking the packet length. A remote RDP client with an active session can send a truncated event to trigger a WinPR stream assertion and abort the server process.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed FreeRDP version, for example with `xfreerdp /version` or your package manager, and compare against `3.32.2`.
- Confirm whether your server runs FreeRDP with assertions enabled (debug or non-release builds); the sources do not say which default build setting is affected.

## Fix

- FreeRDP `3.0.0` before `3.32.2`: move to `3.32.2`.

## Timeline

- 2026-11-04T16:28:11+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121951

## Documents

- [advisory] Vendor advisory: github.com https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-4qq4-qwxq-49m8
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/freerdp-3.0.0-before-3.32.2-denial-of-service-via-slow-path-input-event

## From the sources

FreeRDP 3.0.0 before 3.32.2 server-side RDP peer input parsing skips the six-byte body of a slow-path input event with an unknown message type without checking it lies within the packet's declared length, causing a WinPR stream assertion failure. A remote RDP client with an active session can send a truncated unknown input event to abort assertion-enabled server processes, causing denial of service.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_