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9.8
CVE-2026-15158: Blocksy Companion plugin for WordPress allows malicious file uploads
CVE-2026-15158
Summary
The Blocksy Companion plugin for WordPress has a security flaw that lets attackers upload files that could run malicious code. This is a concern because it could allow hackers to take control of a website. To stay safe, update the plugin to the latest version, especially if you have the premium version and other specific extensions installed.
Original title
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 ext...
Original 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.
nvd CVSS3.1
9.8
Vulnerability type
CWE-434
Unrestricted File Upload
Published: 9 Jul 2026 · Updated: 20 Jul 2026 · First seen: 9 Jul 2026