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Fencer Vulns
medium 5.4

CVE-2021-27370 json

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

published 2021-02-22 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-14128

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.3%
EPSS 3.3% chance of exploitation in 30 days, percentile 88%
public exploits
1
Exploit-DB

Summary

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

Timeline

  1. Published
  2. First public exploit (EDB-49582)

Exploit prediction

3.27% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-49582 Monica 2.19.1 - 'last_name' Stored XSS webapps, 2021-02-23
  • github.com https://github.com/monicahq/monica/pull/4543 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/monicahq/monica/issues/4888 referenced PoC, tagged "exploit" by a source, unverified
  • packetstormsecurity.com http://packetstormsecurity.com/files/161501/Monica-2.19.1-Cross-Site-Scripting.html referenced PoC, tagged "exploit" by a source, unverified
  • huntr.dev https://huntr.dev/bounties/2-other-monica/ 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

Sources

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.