CVE-2026-15158
Received Received - Intake

Arbitrary File Upload in Blocksy Companion WordPress Plugin

Publication date: 2026-07-09

Last updated on: 2026-07-09

Assigner: Wordfence

Description
The Blocksy Companion plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 2.1.46 via the save_attachments function. This is due to the Custom Fonts extension registering a wp_check_filetype_and_ext filter that approves any filename containing .woff2 or .ttf as a substring via strpos() rather than validating that those strings appear as the final extension via PATHINFO_EXTENSION — allowing double-extension filenames such as shell.woff2.php to pass MIME validation and be handled as permitted font files. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible. This vulnerability is only exploitable when the premium version of the plugin (blocksy-companion-pro) is installed with both the WooCommerce Extra (Advanced Reviews) and Custom Fonts extensions active; the free blocksy-companion plugin does not contain the vulnerable code paths.

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Meta Information

Published
2026-07-09
Last Modified
2026-07-09
Generated
2026-07-09
AI Q&A
2026-07-09
EPSS Evaluated
N/A
NVD
CVE-2026-15158
EUVD
EUVD-2026-42549

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
blocksy companion to 2.1.46 (inc)
blocksy blocksy_companion_pro to 2.1.46 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-434 The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.

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Executive Summary

The Blocksy Companion plugin for WordPress has a vulnerability in versions up to and including 2.1.46 that allows arbitrary file uploads. This happens because the Custom Fonts extension uses a filter that approves any filename containing '.woff2' or '.ttf' anywhere in the name, rather than ensuring these are the actual file extensions. As a result, files with double extensions like 'shell.woff2.php' can bypass MIME type validation and be treated as allowed font files.

This flaw enables unauthenticated attackers to upload potentially executable files, which can lead to remote code execution on the affected system.

Note that this vulnerability is only exploitable when the premium version of the plugin (blocksy-companion-pro) is installed with both the WooCommerce Extra (Advanced Reviews) and Custom Fonts extensions active. The free version of the plugin does not contain this vulnerable code.

Impact Analysis

This vulnerability can have severe impacts because it allows unauthenticated attackers to upload arbitrary files that may be executable. This can lead to remote code execution, meaning attackers could run malicious code on your server.

Such an exploit could compromise the integrity, confidentiality, and availability of your website and server, potentially leading to data breaches, defacement, or full system takeover.

Mitigation Strategies

To mitigate this vulnerability, immediately update the Blocksy Companion plugin and its premium version (blocksy-companion-pro) to a version later than 2.1.46 where the issue is fixed.

If updating is not immediately possible, disable the premium version of the plugin or deactivate both the WooCommerce Extra (Advanced Reviews) and Custom Fonts extensions, as the vulnerability is only exploitable when these are active.

Additionally, restrict file upload permissions and monitor for any suspicious file uploads, especially files with double extensions like .woff2.php.

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