What is CVE-2021-43009?

CVE-2021-43009 is a medium-severity vulnerability in Opservices Opmon, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2022-04-08.

How severe is CVE-2021-43009?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Is CVE-2021-43009 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in Opservices Opmon

CVE-2021-43009

A Cross Site Scripting (XSS) vulnerability exists in OpServices OpMon through 9.11 via the search parameter in the request URL.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2022-04-08 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.023 (82.6th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 83rd percentile — 82.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.023 · newest: 0.023 · change: 0.000

Affected products

Opservices Opmon

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

packetstormsecurity.com/files/166619/Opmon-9.11-Cross-Site-Scripting.html (Exploit, VDB Entry, Third Party Advisory)
www.exploit-db.com/exploits/50857 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-43009?: CVE-2021-43009 is a medium-severity vulnerability in Opservices Opmon, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2022-04-08.
How severe is CVE-2021-43009?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2021-43009 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.