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

published 2021-02-22 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-14310

cvss: 5.4; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits: 0; none known

Exploit prediction

0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/monicahq/monica/pull/4543 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD	2.0	3.5	AV:N/AC:M/Au:S/C:N/I:P/A:N

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

github.com /monicahq/monica/pull/4543
exploit, third-party-advisory
github.com /monicahq/monica/issues/4888
issue-tracking, third-party-advisory

Sources

CVE List CVE-2021-27559
NVD CVE-2021-27559

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary