Blocksy Companion <= 2.1.57 - Authenticated (Author+) Stored Cross-Site Scripting via SVG File Upload
- ID
- WPSEC-2026-0353
- Plugin
- Blocksy Companion (blocksy-companion)
- Affected
- all versions before 2.1.58
- Remediation
- Update to 2.1.58 or later.
- CVSS 3.1
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- Weakness
- CWE-79
- Usage
- Plugin Medium · Affected versions Medium among sites WPSec scans, 2026-10-22
- Attack surface
- Blocksy Companion on WPSec AttackSurface
- Fix released
- Published
Description
The Blocksy Companion plugin for WordPress is vulnerable to Stored Cross-Site Scripting via SVG file uploads in all versions up to, and including, 2.1.57 due to SVG sanitization only being hooked to the wp_handle_upload_prefilter filter. SVG files uploaded through other paths that the plugin also allows, such as raw-body uploads to the REST API media endpoint (wp_handle_sideload) and XML-RPC media uploads (wp_upload_bits), are stored without sanitization. This makes it possible for authenticated attackers, with author-level access and above, to upload SVG files containing arbitrary web scripts that will execute whenever a user accesses the uploaded file.
References
- https://wpsec.com/vuln/WPSEC-2026-0353/
- https://plugins.svn.wordpress.org/blocksy-companion/tags/2.1.58/
- https://wordpress.org/plugins/blocksy-companion/
Published by WPSec. Provided as is, without warranty. Corrections: contact us.
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