What is CVE-2021-34815?

CVE-2021-34815 is a medium-severity vulnerability in Checksec Canopy, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2021-06-18.

How severe is CVE-2021-34815?

Medium severity. CVSS v3 base score is 4.8 out of 10.

XSS in Checksec Canopy

CVE-2021-34815

CheckSec Canopy before 3.5.2 allows XSS attacks against the login page via the LOGIN_PAGE_DISCLAIMER parameter.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-06-18 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.008 (56.3th percentile), scored 2026-10-04.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 56.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Checksec Canopy

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

www.checksec.com/canopy.html (Product)
www.compass-security.com/en/research/advisories (Third Party Advisory)
www.compass-security.com/fileadmin/Research/Advisories/2021-10_CSNC-2021-015-Ch… (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-34815?: CVE-2021-34815 is a medium-severity vulnerability in Checksec Canopy, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2021-06-18.
How severe is CVE-2021-34815?: Medium severity. CVSS v3 base score is 4.8 out of 10.