CVE-2021-4467

CVE-2021-4467 is a high-severity vulnerability with a CVSS 4.0 base score of 8.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-400.

Key facts

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.

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 severe is CVE-2021-4467?
CVE-2021-4467 has a CVSS 4.0 base score of 8.7, rated high severity.
Is CVE-2021-4467 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2021-4467?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2021-4467 have an EU (EUVD) identifier?
Yes. CVE-2021-4467 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34719.
When was CVE-2021-4467 published?
CVE-2021-4467 was published on 2025-11-14 and last updated on 2026-06-17.

References

Other CWE-400 (Uncontrolled Resource Consumption) vulnerabilities

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