---
id: CVE-2026-109246
title: >-
  FreeRDP before 3.32.0 contains a divide-by-zero vulnerability in the
  freerdp-shadow-cli shadow server: the frame id in a client's Frame Acknowledge
  PDU is stored without a range check, so the in-flight frame count in
  shadow_encoder_infli…
summary: >-
  FreeRDP before 3.32.0 contains a divide-by-zero vulnerability in the
  freerdp-shadow-cli shadow server: the frame id in a client's Frame Acknowledge
  PDU is stored without a range check, so the in-flight frame count in
  shadow_encoder_infli…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-191
published: '2026-10-12'
updated: '2026-10-12'
sourceUpdated: '2026-10-12T17:17:15.630'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-109246'
references:
  - url: 'https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6vjv-4hm3-6698'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/freerdp-before-3.32.0-shadow-server-divide-by-zero-via-frame-acknowledge-pdu
    label: disclosure@vulncheck.com
tags:
  - nvd
ingestedAt: '2026-10-12T18:00:08.174Z'
---

## Overview

FreeRDP before 3.32.0 contains a divide-by-zero vulnerability in the freerdp-shadow-cli shadow server: the frame id in a client's Frame Acknowledge PDU is stored without a range check, so the in-flight frame count in shadow_encoder_inflight_frames() can underflow. An authenticated client can acknowledge a frame id one greater than the last frame sent, causing shadow_encoder_create_frame_id() to divide by zero (SIGFPE) and terminate the process, disconnecting all viewers.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.