What is CVE-2021-27237?

CVE-2021-27237 is a medium-severity vulnerability in Blackcat-Cms Blackcat Cms, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2021-02-16.

How severe is CVE-2021-27237?

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

XSS in Blackcat-Cms Blackcat Cms

CVE-2021-27237

The admin panel in BlackCat CMS 1.3.6 allows stored XSS (by an admin) via the Display Name field to backend/preferences/ajax_save.php.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-02-16 · 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: 0.010 (60.0th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 60th percentile — 60.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Blackcat-Cms Blackcat Cms — versions 1.3.6

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/BlackCatDevelopment/BlackCatCMS/commits/release-1.4/upload/backend/p… (Patch, Third Party Advisory)
github.com/BlackCatDevelopment/BlackCatCMS/compare/1.3.6...1.4Beta (Patch, Third Party Advisory)
www.exploit-db.com/exploits/49565 (Exploit, VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2021-27237?: CVE-2021-27237 is a medium-severity vulnerability in Blackcat-Cms Blackcat Cms, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2021-02-16.
How severe is CVE-2021-27237?: Medium severity. CVSS v3 base score is 4.8 out of 10.