Vulnerability Report

CVE-2026-15158

RCE

Title: Arbitrary File Upload and RCE in Blocksy Companion plugin for WordPress

RCE

Proof Of Concept

PoC Available for CVE-2026-15158

CWE Category CWE-434

Published Date Jul 09, 2026

Modified Date Jul 09, 2026

Exploit Status Available

Score 9.8 CVSS v3.1

Exploit Probability (EPSS)

0.61%

Vulnerability Summary

CVE-2026-15158: 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.

Impacted Vendors

Analysis in Progress...

Reference Links

https://plugins.trac.wordpress.org/browser/blocksy-companion/tags/2.1.46/framework/premium/extensions/custom-fonts/extension.php#L137 https://plugins.trac.wordpress.org/browser/blocksy-companion/tags/2.1.46/framework/premium/extensions/woocommerce-extra/features/advanced-reviews/feature.php#L811 https://www.wordfence.com/threat-intel/vulnerabilities/id/2df449b4-3f3b-4afc-b391-8d8d11710c07?source=cve

CVSS v3.1

Source Entity [email protected]

Severity CRITICAL

9.8

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-15158 Exploits & PoCs (Proof Of Concept)

GitHub https://github.com/shinthink/CVE-2026-58480

View Code

July 09, 2026 MODIFIED

Vulnerability data updated via NVD.

July 09, 2026 MODIFIED

Vulnerability data updated via NVD.

July 09, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


                                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Stack

No specific products linked.