What is CVE-2021-40541?

CVE-2021-40541 is a medium-severity vulnerability in Php-Fusion Phpfusion, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-10-11.

How severe is CVE-2021-40541?

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

XSS in Php-Fusion Phpfusion

CVE-2021-40541

PHPFusion 9.03.110 is affected by cross-site scripting (XSS) in the preg patterns filter html tag without "//" in descript() function An authenticated user can trigger XSS by appending "//" in the end of text.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-10-11 · 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: 0.006 (45.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 45.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Php-Fusion Phpfusion — versions 9.03.110

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/PHPFusion/PHPFusion/issues/2373 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2021-40541?: CVE-2021-40541 is a medium-severity vulnerability in Php-Fusion Phpfusion, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-10-11.
How severe is CVE-2021-40541?: Medium severity. CVSS v3 base score is 6.1 out of 10.