What is CVE-2021-40303?

CVE-2021-40303 is a medium-severity vulnerability in Perfexcrm Perfex Crm, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2022-11-08.

How severe is CVE-2021-40303?

Medium severity. CVSS v3 base score is 5.4 out of 10.

Is CVE-2021-40303 known to be exploited?

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

XSS in Perfexcrm Perfex Crm

CVE-2021-40303

perfex crm 1.10 is vulnerable to Cross Site Scripting (XSS) via /clients/profile.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2022-11-08 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (42.6th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 42.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000

Affected products

Perfexcrm Perfex Crm — versions 1.10

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

zecopro/CVE-2021-40303

References

www.exploit-db.com/exploits/50097 (Exploit, VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2021-40303?: CVE-2021-40303 is a medium-severity vulnerability in Perfexcrm Perfex Crm, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2022-11-08.
How severe is CVE-2021-40303?: Medium severity. CVSS v3 base score is 5.4 out of 10.
Is CVE-2021-40303 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.