CVE-2026-15158

CRITICAL

Blocksy Companion <= 2.1.46 - Unauthenticated Arbitrary File Upload via 'blc-review-images[]' Parameter

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-15158. PoCs published by shinthink.

AI-analyzed exploit summary This PoC exploits CVE-2026-15158/CVE-2026-58480, an unauthenticated arbitrary file upload vulnerability in Blocksy Companion Pro < 2.1.47. The exploit bypasses file extension validation via a strpos() substring check in the Custom Fonts extension using double-extension filenames (e.g., shell.woff2.php) to achieve remote code execution.

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.

Exploits (1)

github WORKING POC
by shinthink · pythonpoc
https://github.com/shinthink/CVE-2026-58480

This PoC exploits CVE-2026-15158/CVE-2026-58480, an unauthenticated arbitrary file upload vulnerability in Blocksy Companion Pro < 2.1.47. The exploit bypasses file extension validation via a strpos() substring check in the Custom Fonts extension using double-extension filenames (e.g., shell.woff2.php) to achieve remote code execution.

Classification
Working Poc 98%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Blocksy Companion Pro < 2.1.47 (with Advanced Reviews and Custom Fonts extensions active)
No auth needed
Prerequisites: Blocksy Companion Pro < 2.1.47 installed · Advanced Reviews (WooCommerce Extra) extension active · Custom Fonts extension active
mistral-large-3 · analyzed Jul 26, 2026 Full analysis →

Scores

CVSS v3 9.8
EPSS 0.0061
EPSS Percentile 45.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact total

Details

CWE
CWE-434
Status published
Products (1)
creativethemeshq/Blocksy Companion < 2.1.46
Published Jul 09, 2026
Tracked Since Jul 09, 2026