CVE-2021-41380 : What You Need to Know

RealVNC Viewer 6.21.406 allows remote VNC servers to cause a denial of service (application crash) via crafted RFB protocol data. This issue is disputed and requires social engineering to exploit.

Understanding CVE-2021-41380

What is CVE-2021-41380?

CVE-2021-41380 involves a vulnerability in RealVNC Viewer 6.21.406 where remote VNC servers can trigger a denial of service by sending manipulated RFB protocol data. The impact is on application stability.

The Impact of CVE-2021-41380

Remote VNC servers can induce a denial of service, causing the VNC Viewer application to crash.
The issue requires social engineering to convince a user to connect to a fake VNC server.

Technical Details of CVE-2021-41380

Vulnerability Description

The vulnerability allows malicious VNC servers to crash the RealVNC Viewer application by sending specific RFB protocol data.

Affected Systems and Versions

Affected Versions: RealVNC Viewer 6.21.406

Exploitation Mechanism

Attackers need to trick users into connecting to a malicious VNC server.

Mitigation and Prevention

Immediate Steps to Take

Refrain from connecting to unknown or untrusted VNC servers.
Regularly update RealVNC Viewer to the latest version.

Long-Term Security Practices

Educate users on social engineering tactics and the risks of connecting to unverified servers.
Implement network-level security measures to detect and block malicious VNC server connections.
Consider using alternative VNC viewer applications with robust security features.

Patching and Updates

Ensure that RealVNC Viewer is kept up to date with the latest security patches and fixes.