CVE-2026-15158: CWE-434 Unrestricted Upload of File with Dangerous Type in creativethemeshq Blocksy Companion
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.
AI Analysis
Technical Summary
CVE-2026-15158 is a critical vulnerability in the Blocksy Companion WordPress plugin (creativethemeshq) affecting all versions up to 2.1.46. The issue arises from improper validation in the Custom Fonts extension, where the wp_check_filetype_and_ext filter uses strpos() to check for .woff2 or .ttf substrings anywhere in the filename rather than validating the actual file extension. This allows files with double extensions such as shell.woff2.php to bypass MIME checks and be treated as permitted font files. The vulnerability is exploitable only when the premium blocksy-companion-pro plugin is installed with both WooCommerce Extra (Advanced Reviews) and Custom Fonts extensions active. This enables unauthenticated attackers to upload potentially executable files, leading to remote code execution.
Potential Impact
An unauthenticated attacker can upload arbitrary files with executable code due to improper file type validation, potentially resulting in remote code execution on the affected system. This compromises confidentiality, integrity, and availability of the WordPress site running the vulnerable plugin with the specified extensions.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should disable the premium blocksy-companion-pro plugin or the WooCommerce Extra (Advanced Reviews) and Custom Fonts extensions to prevent exploitation. Monitor vendor channels for updates and apply official patches once released.
CVE-2026-15158: CWE-434 Unrestricted Upload of File with Dangerous Type in creativethemeshq Blocksy Companion
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.
CVSS v3.1
Score 9.8critical
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-15158 is a critical vulnerability in the Blocksy Companion WordPress plugin (creativethemeshq) affecting all versions up to 2.1.46. The issue arises from improper validation in the Custom Fonts extension, where the wp_check_filetype_and_ext filter uses strpos() to check for .woff2 or .ttf substrings anywhere in the filename rather than validating the actual file extension. This allows files with double extensions such as shell.woff2.php to bypass MIME checks and be treated as permitted font files. The vulnerability is exploitable only when the premium blocksy-companion-pro plugin is installed with both WooCommerce Extra (Advanced Reviews) and Custom Fonts extensions active. This enables unauthenticated attackers to upload potentially executable files, leading to remote code execution.
Potential Impact
An unauthenticated attacker can upload arbitrary files with executable code due to improper file type validation, potentially resulting in remote code execution on the affected system. This compromises confidentiality, integrity, and availability of the WordPress site running the vulnerable plugin with the specified extensions.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should disable the premium blocksy-companion-pro plugin or the WooCommerce Extra (Advanced Reviews) and Custom Fonts extensions to prevent exploitation. Monitor vendor channels for updates and apply official patches once released.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Wordfence
- Date Reserved
- 2026-07-08T20:08:13.444Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4f678568715ace430cb609
Added to database: 07/09/2026, 09:19:01 UTC
Last enriched: 07/16/2026, 10:08:30 UTC
Last updated: 08/22/2026, 10:52:07 UTC
Views: 68
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