CVE-2021-4467

Published Nov 14, 2025 Modified Apr 15, 2026 CWE-400

Description

Positive Technologies MaxPatrol 8 and XSpider contain a remote denial-of-service vulnerability in the client communication service on TCP port 2002. The service generates a new session identifier for each incoming connection without adequately limiting concurrent requests. An unauthenticated remote attacker can repeatedly issue HTTPS requests to the service, causing excessive allocation of session identifiers. Under load, session identifier collisions may occur, forcing active client sessions to disconnect and resulting in service disruption.

Is your site exposed to CVE-2021-4467?

Run a free security scan — no signup, results in seconds.

Weakness Type (CWE)

CWE-400 Uncontrolled Resource Consumption

References

Frequently Asked Questions

What is CVE-2021-4467? +
Positive Technologies MaxPatrol 8 and XSpider contain a remote denial-of-service vulnerability in the client communication service on TCP port 2002. The service generates a new session identifier for each incoming connection without adequately limiting concurrent requests. An unauthenticated remote attacker can repeatedly issue HTTPS requests to the service, causing excessive allocation of session identifiers. Under load, session identifier collisions may occur, forcing active client sessions to disconnect and resulting in service disruption.
How do I check if I'm vulnerable to CVE-2021-4467? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2021-4467 — free, no signup required.