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Fencer Intel
medium 6.1

CVE-2020-21054 json

Cross Site Scripting (XSS) vulnerability in FusionPBX 4.5.7 allows remote malicious users to inject arbitrary web script or HTML via an uns…

published 5y ago modified 4mo ago also EUVD-2020-13833

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 54%
public exploits
0
none known

Summary

Cross Site Scripting (XSS) vulnerability in FusionPBX 4.5.7 allows remote malicious users to inject arbitrary web script or HTML via an unsanitized "f" variable in app\vars\vars_textarea.php.

Patch / fix

Is CVE-2020-21054 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

0.72% chance of exploitation in the next 30 days, higher than 54% 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.