CVE-2021-24687Network attack vector

Admin-level stored XSS via unescaped settings attributes

Published Oct 4, 2021 · Updated Aug 3, 2024

Stored XSS in Webnus Modern Events Calendar Lite before 5.22.2 allows remote authenticated users to execute script in an administrator's browser. The plugin stores high-privilege settings values and writes them into HTML attributes without context-appropriate escaping; public sources do not identify the affected setting names or code path. Administrator-level access is required, and exploitation changes page content executed when another user views the affected output.

CVSS severity4.8
Medium
EPSS probability0.62%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Webnus Modern Events Calendar Lite before 5.22.2 allows remote authenticated users to execute script in an administrator's browser. The plugin stores high-privilege settings values and writes them into HTML attributes without context-appropriate escaping; public sources do not identify the affected setting names or code path. Administrator-level access is required, and exploitation changes page content executed when another user views the affected output.

The record

CVE
CVE-2021-24687
Published
Oct 4, 2021
Updated
Aug 3, 2024
Vendor
Webnus
Product
Modern Events Calendar Lite
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Oct 4, 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=5.22.2 <5.22.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Webnus · Modern Events Calendar Liteversion=5.22.2 <5.22.2

Published CVSS scores

4.8NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
3.5NVDAV: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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Cross-site Scripting (XSS)
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

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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