CVE intelligence and bounded remediation

CVE-2021-24171 — The WooCommerce Upload Files WordPress plugin before 59.4 ran a single sanitization pass to remove blocked extensions such as .php

Critical CVSS 9.8

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.

Severity
Critical
CVSS
9.8 (3.1)
Published
2021-04-05
CISA KEV
Not currently listed
Ecosystem
php/wordpress
Weaknesses
CWE-434

Affected products

  • vanquish / woocommerce_upload_files

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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