CVE-2021-24604Public exploitNetwork attack vector

Stored XSS via unescaped category names

Published Sep 20, 2021 · Updated Aug 3, 2024

Stored XSS in Offshore Web Master Availability Calendar before 1.2.2 allows remote authenticated users to execute script through category names. The plugin stores category Name input without sanitization and later emits it without escaping when the associated shortcode renders a page or post. High-privilege access is required to create the category, and script execution occurs when a user views shortcode output containing the crafted name.

CVSS severity4.8
Medium
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Offshore Web Master Availability Calendar before 1.2.2 allows remote authenticated users to execute script through category names. The plugin stores category Name input without sanitization and later emits it without escaping when the associated shortcode renders a page or post. High-privilege access is required to create the category, and script execution occurs when a user views shortcode output containing the crafted name.

The record

CVE
CVE-2021-24604
Published
Sep 20, 2021
Updated
Aug 3, 2024
Vendor
Offshore Web Master
Product
Availability Calendar
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Sep 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.2.2 <1.2.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Offshore Web Master · Availability Calendarversion=1.2.2 <1.2.2

Published CVSS scores

4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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