CVE-2026-22859
📋 TL;DR
This vulnerability in FreeRDP allows remote attackers to cause an out-of-bounds read by sending specially crafted MSUSB_INTERFACE_DESCRIPTOR values. This could lead to information disclosure or potentially remote code execution. Anyone using FreeRDP versions before 3.20.1 for remote desktop connections is affected.
💻 Affected Systems
- FreeRDP
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise of the FreeRDP client machine
Likely Case
Information disclosure through memory leaks, potentially exposing sensitive data or causing application crashes
If Mitigated
Denial of service through application crashes if memory corruption doesn't lead to code execution
🎯 Exploit Status
Exploitation requires the attacker to control or compromise an RDP server that the victim connects to. The vulnerability is in the client-side processing of server responses.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.20.1
Vendor Advisory: https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-56f5-76qv-2r36
Restart Required: Yes
Instructions:
1. Download FreeRDP 3.20.1 or later from the official repository. 2. Uninstall the current version. 3. Install the patched version. 4. Restart any applications using FreeRDP.
🔧 Temporary Workarounds
Disable USB Redirection
allDisable the URBDRC feature that contains the vulnerable code path
xfreerdp /usb:id,dev:disable
wfreerdp /usb:id,dev:disable
Network Segmentation
allRestrict RDP connections to trusted servers only using firewall rules
🧯 If You Can't Patch
- Disable USB redirection feature in FreeRDP client configuration
- Use alternative RDP clients or VPN solutions for remote access
🔍 How to Verify
Check if Vulnerable:
Check FreeRDP version with 'xfreerdp --version' or 'wfreerdp --version'. If version is below 3.20.1, the system is vulnerable.Check Version:
xfreerdp --version 2>&1 | head -1Verify Fix Applied:
After patching, verify version is 3.20.1 or higher using the version command📡 Detection & Monitoring
Log Indicators:
- FreeRDP crash logs
- Segmentation fault errors in system logs when using RDP
- Unexpected memory access errors
Network Indicators:
- RDP connections to untrusted servers
- Unusual RDP traffic patterns
SIEM Query:
source="*freerdp*" AND ("segmentation fault" OR "out of bounds" OR "memory violation")