High severity · published Nov 14, 2025
CVE-2021-4467
Positive Technologies MaxPatrol 8 & XSpider Remote DoS
8.7
CVSS
0.5%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 42% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
M8
MaxPatrol 8 (Server) · Positive Technologies
through 09.2020 · source: vendor
XS
XSpider (Server) · Positive Technologies
through 09.2020 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-4467
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-4467
cxsecurity.com
https://cxsecurity.com/issue/WLB-2021090114
vulners.com
https://vulners.com/zdt/1337DAY-ID-36775
www.ptsecurity.com
https://www.ptsecurity.com/
www.vulncheck.com
https://www.vulncheck.com/advisories/positive-technologies-maxpatrol-8-and-xspider-remote-dos
