CVE-2026-22853
📋 TL;DR
CVE-2026-22853 is a critical heap buffer overflow vulnerability in FreeRDP's RDPEAR component that allows attackers to execute arbitrary code or cause denial of service. The vulnerability affects FreeRDP implementations prior to version 3.20.1. Any system using vulnerable FreeRDP versions for remote desktop connections is at risk.
💻 Affected Systems
- FreeRDP
📦 What is this software?
Freerdp by Freerdp
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with SYSTEM/root privileges leading to complete system compromise, data theft, and lateral movement within networks.
Likely Case
Remote code execution with user-level privileges or denial of service crashing the FreeRDP client/server process.
If Mitigated
Denial of service only if exploit fails or memory protections prevent code execution.
🎯 Exploit Status
The vulnerability requires sending specially crafted RDPEAR packets. No authentication needed for exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.20.1
Vendor Advisory: https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-47v9-p4gp-w5ch
Restart Required: Yes
Instructions:
1. Download FreeRDP 3.20.1 from official repository. 2. Stop all FreeRDP services. 3. Install/compile new version. 4. Restart services/applications using FreeRDP.
🔧 Temporary Workarounds
Network Segmentation
linuxRestrict RDP traffic to trusted networks only using firewall rules.
iptables -A INPUT -p tcp --dport 3389 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 3389 -j DROP
Disable RDPEAR
allDisable RDPEAR functionality if not required.
freerdp /sec:rdp /gfx:off /rfx:off /network:auto
🧯 If You Can't Patch
- Implement strict network access controls to limit RDP connections to trusted sources only.
- Deploy application control solutions to prevent execution of unauthorized code from FreeRDP processes.
🔍 How to Verify
Check if Vulnerable:
Check FreeRDP version with 'xfreerdp --version' or 'wfreerdp.exe --version'. If version is below 3.20.1, system is vulnerable.Check Version:
xfreerdp --version 2>&1 | head -1Verify Fix Applied:
After patching, verify version is 3.20.1 or higher using version check command.📡 Detection & Monitoring
Log Indicators:
- FreeRDP process crashes
- Memory access violation errors in system logs
- Unexpected FreeRDP termination
Network Indicators:
- Unusual RDPEAR protocol traffic patterns
- Multiple connection attempts to RDP ports
- Malformed RDP packets
SIEM Query:
source="*freerdp*" AND (event_type="crash" OR event_type="access_violation")