Blog

"Prevention is cheaper than a breach"

Home / Threats / CVE-2021-24253

CVE-2021-24253 - Classyfrieds Plugin

CVE-2021-24253

The Classyfrieds WordPress plugin through 3.8 does not properly check the uploaded file when an authenticated user adds a listing, only checking the content-type in the request. This allows any authenticated user to upload arbitrary PHP files via the Add Listing feature of the plugin, leading to RCE.

CVE-2021-24253

HIGH CVSS 8.8 Published 2021-05-06 Updated 2024-11-21
AI Risk Critical (100/100) Active Exploit: Likely Published Exploit: Public exploit references found Priority: P1 Immediate
Severity Band HIGH
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected Components 2
Reference Links 2
AI Risk Engine Critical (100/100)
Exploitability High
Active Exploitation Likely
Published Exploit Status Public exploit references found

Threat Timeline

  1. 2021-05-06 CVE published and first recorded in the threat feed.
  2. 2024-11-21 Record updated with latest vulnerability metadata.
  3. 2026-04-10 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 5 days ago

AI enriched 5 days ago (2026-04-10 20:43 UTC)

Technical Summary

The Classyfrieds WordPress plugin through 3.8 does not properly check the uploaded file when an authenticated user adds a listing, only checking the content-type in the request. This allows any authenticated user to upload arbitrary PHP files via the Add Listing feature of the plugin, leading to RCE.

Potential Impact

Severity is HIGH (CVSS 8.8). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.

Exploitability Assessment

Exploitability is assessed as High based on published exploit references, remote code execution potential.

Primary risk drivers: published exploit references, remote code execution potential

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 100/100 (Critical, High) with priority P1 Immediate. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

Affected Products

Classyfrieds PLUGIN · classyfrieds Affected: <= 3.8 Fixed version not specified
Through 3 PLUGIN · through-3 Affected range not specified Fixed version not specified
Scroll to top