---
id: "CVE-2026-121405"
kind: "vulnerability"
aliases: ["CVE-2026-121405"]
title: "FreeRDP: unbounded serial IRP buffer lets a malicious server exhaust client memory"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["freerdp", "linux", "package", "rdp-clients", "windows"]
not_affected_if: ["fixed-version", "no-serial-redirection", "trusted-servers-only"]
published_at: "2026-11-03T15:17:29+00:00"
first_seen_at: "2026-11-03T15:21:58+00:00"
updated_at: "2026-11-03T15:24:29+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121405", "first_seen_at": "2026-11-03T15:21:58+00:00"}]
---

# FreeRDP: unbounded serial IRP buffer lets a malicious server exhaust client memory

FreeRDP before 3.32.2 does not cap the OutputBufferLength in serial device-control IRP requests. A malicious RDP server with serial redirection can make the client allocate excessive memory, exhausting it.

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

## How to check

- Check the installed FreeRDP version, for example `xfreerdp /version`, and compare it with the fixed version.
- Look for serial port redirection enabled in RDP client sessions (unknown exact setting name in sources).

## Fix

- FreeRDP: upgrade to `3.32.2` or later.

## Timeline

- 2026-11-03T15:21:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121405

## Documents

- [advisory] Vendor advisory: github.com https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-r387-jjq3-87hv
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/freerdp-before-3.32.2-memory-exhaustion-via-serial-rdpdr-device-control

## From the sources

FreeRDP before 3.32.2 fails to cap the OutputBufferLength in serial device-control IRP requests, allowing malicious servers to trigger excessive memory allocation. Attackers running a server with serial redirection can send an IRP_MJ_DEVICE_CONTROL request with IOCTL_USBPRINT_GET_1284_ID and a near-maximum length to exhaust client memory.

---

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