CVE-2026-23732 – FreeRDP clients prior to version 3.21.0 contain... (How to Fix)

Q: What is the severity of CVE-2026-23732?

CVE-2026-23732 has a CVSS score of 7.5 (HIGH). FreeRDP clients prior to version 3.21.0 contain a buffer overflow vulnerability in FastGlyph parsing. A malicious RDP server can exploit this to cause a denial-of-service (client crash) by sending specially crafted packets. All FreeRDP client users connecting to untrusted servers are affected.

📋 TL;DR

FreeRDP clients prior to version 3.21.0 contain a buffer overflow vulnerability in FastGlyph parsing. A malicious RDP server can exploit this to cause a denial-of-service (client crash) by sending specially crafted packets. All FreeRDP client users connecting to untrusted servers are affected.

💻 Affected Systems

Products:

FreeRDP

Versions: All versions prior to 3.21.0

Operating Systems: Linux, Windows, macOS, BSD

Default Config Vulnerable: ⚠️ Yes

Notes: Any system using FreeRDP client to connect to RDP servers is vulnerable

📦 What is this software?

Freerdp by Freerdp

View all CVEs affecting Freerdp →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to full client compromise, though CVSS suggests DoS is primary impact

🟠

Likely Case

Client crash/denial-of-service when connecting to malicious server

🟢

If Mitigated

No impact if patched version used or connections restricted to trusted servers

🌐 Internet-Facing: MEDIUM - Requires client to connect to malicious server, but RDP clients often connect to various servers

🏢 Internal Only: LOW - Internal RDP servers are typically trusted, reducing attack surface

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Exploitation requires client to connect to malicious server; server-side control needed

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 3.21.0

Vendor Advisory: https://github.com/FreeRDP/FreeRDP/releases/tag/3.21.0

Restart Required: Yes

Instructions:

1. Download FreeRDP 3.21.0 or newer from official repository
2. Compile and install following platform-specific build instructions
3. Restart any FreeRDP client applications

🔧 Temporary Workarounds

Restrict RDP Connections

all

Only allow FreeRDP connections to trusted, internal RDP servers

🧯 If You Can't Patch

Discontinue use of FreeRDP for connecting to untrusted RDP servers
Use alternative RDP client software that is not vulnerable

🔍 How to Verify

Check if Vulnerable:

Check FreeRDP version with 'xfreerdp --version' or equivalent command

Check Version:

xfreerdp --version

Verify Fix Applied:

Verify version is 3.21.0 or higher after update

📡 Detection & Monitoring

Log Indicators:

FreeRDP client crashes with segmentation faults
Unexpected termination of RDP sessions

Network Indicators:

RDP connections to unknown/untrusted servers
Unusual RDP traffic patterns

SIEM Query:

source="freerdp" AND (event="crash" OR event="segmentation_fault")

📊 Metadata

CVE ID: CVE-2026-23732

CVSS v3 Score: 7.5 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE: CWE-122

EPSS Score: 0.09% exploit probability (24.8th percentile)

Published: January 19, 2026

Last Updated: January 28, 2026

🔗 References

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🔗 Related Vulnerabilities

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