Blocksy Companion: Dangerous file upload
Blocksy Companion is affected by dangerous file upload. The vulnerable path is reachable without authentication. Successful exploitation can place attacker-controlled executable content on the server and may lead to full site compromise. The published affected range is <= 2.1.46.
- Component
- Blocksy Companion
- Plugin slug
blocksy-companion- Affected
- <= 2.1.46
- Safe version
2.1.47- Published
- Jul 08, 2026
This CVE was published Jul 08, 2026 and is one of 12 known issues for this plugin.
Update, patch or deactivate.
Update Blocksy Companion to 2.1.47 or later, or disable and remove it until a fixed version is available.
A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.
Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.
Technical description
Blocksy Companion Pro plugin for WordPress before 2.1.47 contains an unauthenticated arbitrary file upload vulnerability that allows attackers to upload executable files by bypassing extension validation in the save_attachments function exposed through the Advanced Reviews feature. Attackers can exploit the Custom Fonts extension's flawed strpos() substring check by uploading double-extension filenames such as shell.woff2.php, causing the validation to pass on the substring match while the web server executes the file as PHP, achieving remote code execution.
CVE / CNA vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X