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Modern Events Calendar Lite - Arbitrary File Upload (CVE-2021-24145)

CVE-2021-24145

Arbitrary file upload in the Modern Events Calendar Lite WordPress plugin, versions before 5.16.5, did not properly check the imported file, allowing PHP ones to be uploaded by administrator by using the 'text/csv' content-type in the request.

CVE-2021-24145

HIGH CVSS 7.2 Published 2021-03-18 Updated 2026-06-17
AI Risk High (76/100) Active Exploit: No strong signal Published Exploit: Public exploit references found Priority: P2 Urgent
Severity Band HIGH
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Affected Components 1
Reference Links 3
AI Risk Engine High (76/100)
Exploitability Medium
Active Exploitation No strong signal
Published Exploit Status Public exploit references found

Threat Timeline

  1. 2021-03-18 CVE published and first recorded in the threat feed.
  2. 2026-06-17 Record updated with latest vulnerability metadata.
  3. 2026-04-11 AI technical context refreshed for mitigation and impact guidance.
  4. Now Monitoring for follow-up changes, linked references, and new related CVEs.

AI Context

Machine-generated threat intelligence

AI Updated 173 days ago

AI enriched 173 days ago (2026-04-11 00:12 UTC)

Technical Summary

Arbitrary file upload in the Modern Events Calendar Lite WordPress plugin, versions before 5.16.5, did not properly check the imported file, allowing PHP ones to be uploaded by administrator by using the 'text/csv' content-type in the request.

Potential Impact

Severity is HIGH (CVSS 7.2). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.

Exploitability Assessment

Exploitability is assessed as Medium based on published exploit references.

Primary risk drivers: published exploit references

Mitigation Recommendations

Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.

Detection & Monitoring

Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.

Business Impact Lens

AI risk score 76/100 (High, Medium) with priority P2 Urgent. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

References

What to do about this

Patch promptly The consequence is significant even where an attacker needs a foothold first.

Fix it

Update Modern Events Calendar Lite to 5.16.5 or later.

That is the complete fix. Everything below is what protects you in the meantime.

Cannot update today? Request / payload inspection (WAF) in Hack Halt ProSecure blocks this class of attack before WordPress processes the request.

Inspect request parameters and bodies for injection, traversal and file-inclusion payloads, and refuse the request rather than logging it.

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Not sure if you are affected?

Scan your site to see whether it runs Modern Events Calendar Lite, and at which version.

Free, no installation, no account. It reads what your site already publishes, then tells you which plugins carry known vulnerabilities and what to do about each one.

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Am I affected by this vulnerability?

You are affected if your site runs Modern Events Calendar Lite. Versions below 5.16.5 are vulnerable; that release and later are not.

How do I fix it?

Update Modern Events Calendar Lite to version 5.16.5 or later. That is the complete fix. Until you can update, Request / payload inspection (WAF) in Hack Halt ProSecure contains this class of attack at the request layer.

What can an attacker actually do?

This is a Arbitrary File Upload flaw. An attacker who exploits it can place an executable file on the server and then run it.