CVE-2021-24147Public exploitNetwork attack vector

Stored XSS via unsanitized event notes

Published Mar 18, 2021 · Updated Aug 3, 2024

Stored XSS in Webnus Modern Events Calendar Lite before 5.16.5 allows remote authenticated users to execute scripts through event notes. The plugin stores the mic_comment field without input sanitization or output encoding and renders it on the event frontend. Author-level access is sufficient to plant the payload, and script execution occurs when a visitor views the affected event.

CVSS severity5.4
Medium
EPSS probability0.75%
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 Webnus Modern Events Calendar Lite before 5.16.5 allows remote authenticated users to execute scripts through event notes. The plugin stores the mic_comment field without input sanitization or output encoding and renders it on the event frontend. Author-level access is sufficient to plant the payload, and script execution occurs when a visitor views the affected event.

The record

CVE
CVE-2021-24147
Published
Mar 18, 2021
Updated
Aug 3, 2024
Vendor
Webnus
Product
Modern Events Calendar Lite
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 18, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=5.16.5 <5.16.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Webnus · Modern Events Calendar Liteversion=5.16.5 <5.16.5

Published CVSS scores

3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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
Privilegesauthenticated
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

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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