What is CVE-2021-27371?

CVE-2021-27371 is a medium-severity vulnerability in Monicahq Monica, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-02-22.

How severe is CVE-2021-27371?

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

XSS in Monicahq Monica

CVE-2021-27371

The Contact page in Monica 2.19.1 allows stored XSS via the Description field.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-02-22 · 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: 0.006 (46.2th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.2% 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

Monicahq Monica — versions 2.19.1

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/monicahq/monica/issues/4888 (Exploit, Third Party Advisory, Issue Tracking)
github.com/monicahq/monica/pull/4543 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-27371?: CVE-2021-27371 is a medium-severity vulnerability in Monicahq Monica, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-02-22.
How severe is CVE-2021-27371?: Medium severity. CVSS v3 base score is 5.4 out of 10.