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Fencer Intel
medium 6.1

CVE-2021-31930 json

Persistent cross-site scripting (XSS) in the web interface of Concerto through 2.3.6 allows an unauthenticated remote attacker to introduce…

published 5y ago modified 4mo ago also EUVD-2021-18803

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 60%
public exploits
0
none known

Summary

Persistent cross-site scripting (XSS) in the web interface of Concerto through 2.3.6 allows an unauthenticated remote attacker to introduce arbitrary JavaScript by injecting an XSS payload into the First Name or Last Name parameter upon registration. When a privileged user attempts to delete the account, the XSS payload will be executed.

Patch / fix

Is CVE-2021-31930 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

0.92% chance of exploitation in the next 30 days, higher than 60% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel 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.