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Fencer Vulns
medium 4.8

CVE-2021-24604 json

Availability Calendar < 1.2.2 - Authenticated Stored Cross-Site Scripting

published 2021-09-20 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-11516

cvss
4.8
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 49%
public exploits
0
none known

Summary

The Availability Calendar WordPress plugin before 1.2.2 does not sanitise or escape its Category Names before outputting them in page/post where the associated shortcode is embed, allowing high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html is disallowed

Patch / fix

  • offshorewebmaster availability_calendar 1.2.2

Exploit prediction

0.62% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • wpscan.com https://wpscan.com/vulnerability/d084c5b1-45f1-4e7e-b3e9-3c98ae4bce9c referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 4.8 CVSS:3.1/AV:N/AC:L/PR:H/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

Affected products

  • Unknown Availability Calendar

Classification

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

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.