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Home / Threats / CVE-2021-24171

CVE-2021-24171 - Before 59 Plugin

CVE-2021-24171

Vulnerability CVE-2021-24171 PLUGIN before-59 CRITICAL

The WooCommerce Upload Files WordPress plugin before 59.4 ran a single sanitization pass to remove blocked extensions such as .php. It was possible to bypass this and upload a file with a PHP extension by embedding a "blocked" extension within another "blocked" extension in the "wcuf_file_name" parameter. It was also possible to perform a double extension attack and upload files to a different location via path traversal using the "wcuf_current_upload_session_id" parameter.

CVE-2021-24171

CRITICAL CVSS 9.8 Published 2021-04-05 Updated 2024-11-25
AI Risk Critical (98/100) Active Exploit: No strong signal Published Exploit: No public exploit references Priority: P1 Immediate
Severity Band CRITICAL
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected Components 2
Reference Links 2
AI Risk Engine Critical (98/100)
Exploitability High
Active Exploitation No strong signal
Published Exploit Status No public exploit references

Threat Timeline

  1. 2021-04-05 CVE published and first recorded in the threat feed.
  2. 2024-11-25 Record updated with latest vulnerability metadata.
  3. 2026-04-12 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 9 days ago

AI enriched 9 days ago (2026-04-12 03:32 UTC)

Technical Summary

The WooCommerce Upload Files WordPress plugin before 59.4 ran a single sanitization pass to remove blocked extensions such as .php. It was possible to bypass this and upload a file with a PHP extension by embedding a "blocked" extension within another "blocked" extension in the "wcuf_file_name" parameter. It was also possible to perform a double extension attack and upload files to a different location via path traversal using the "wcuf_current_upload_session_id" parameter.

Potential Impact

Severity is CRITICAL (CVSS 9.8). 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 remote code execution potential.

Primary risk drivers: 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 98/100 (Critical, High) with priority P1 Immediate. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

Affected Products

Before 59 PLUGIN · before-59 Affected: < 59.4 Fixed in: 59.4
Woocommerce Upload Files PLUGIN · woocommerce-upload-files Affected: < 59.4 Fixed in: 59.4
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