---
id: "CVE-2026-121399"
kind: "vulnerability"
aliases: ["CVE-2026-121399"]
title: "FreeRDP: malicious RD Gateway forces 2 GiB allocation, crashing clients"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["freerdp", "linux", "package", "rd-gateway", "remote-desktop", "windows"]
not_affected_if: ["direct-rdp-only", "no-rd-gateway"]
published_at: "2026-11-03T15:17:28+00:00"
first_seen_at: "2026-11-03T15:21:57+00:00"
updated_at: "2026-11-03T15:24:33+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121399", "first_seen_at": "2026-11-03T15:21:57+00:00"}]
---

# FreeRDP: malicious RD Gateway forces 2 GiB allocation, crashing clients

FreeRDP before 3.32.2 mishandles an RD Gateway packet length field in rdg_receive_packet, so a malicious gateway can make the client allocate 2 GiB before tunnel authentication. An attacker gets pre-authentication memory exhaustion and denial of service against the client.

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

## How to check

- Check the installed FreeRDP version against the range in the advisory: `xfreerdp /version` or the package manager's version query
- Look for FreeRDP builds used as RD Gateway clients on workstations and servers that connect through a gateway

## Fix

- FreeRDP: move to `3.32.2` or later

## Timeline

- 2026-11-03T15:21:57+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121399

## Documents

- [advisory] Vendor advisory: github.com https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-4vh4-3pc3-32p7
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/freerdp-before-3.32.2-memory-exhaustion-via-rd-gateway-packet-length

## From the sources

FreeRDP before 3.32.2 contains a memory allocation vulnerability in rdg_receive_packet that allows a malicious RD Gateway to force a 2 GiB client allocation before tunnel authentication. Attackers can send an eight-byte RDG header declaring packet length 0x7FFFFFFF to trigger pre-authentication memory exhaustion and denial of service.

---

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