CVE-2021-4467Public exploitNetwork attack vector

Remote service interruption via session identifier exhaustion

Published Nov 14, 2025 · Updated Nov 14, 2025

Resource exhaustion in Positive Technologies MaxPatrol 8 and XSpider through 09.2020 allows remote attackers to interrupt client sessions. The TCP port 2002 client communication service creates a session identifier for every HTTPS connection without limiting concurrent requests. Repeated unauthenticated connections exhaust the identifier space, create collisions, and disconnect active clients within minutes.

CVSS severity8.7
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Positive Technologies MaxPatrol 8 and XSpider through 09.2020 allows remote attackers to interrupt client sessions. The TCP port 2002 client communication service creates a session identifier for every HTTPS connection without limiting concurrent requests. Repeated unauthenticated connections exhaust the identifier space, create collisions, and disconnect active clients within minutes.

The record

CVE
CVE-2021-4467
Published
Nov 14, 2025
Updated
Nov 14, 2025
Vendor
Positive Technologies
Product
MaxPatrol 8
Classifications
CWE-400, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=09.2020

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Positive Technologies · MaxPatrol 8version=0 <=09.2020
Positive Technologies · XSpiderversion=0 <=09.2020

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.003Application Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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