CVE-2026-18438: Templately <= 3.7.1 - Authenticated (Contributor+) Arbitrary File Upload to Remote Code Execution via Gutenberg Cloud Import Attachment Filename Mismatch

The Templately – Elementor & Gutenberg Template Library: 6500+ Free & Pro Ready Templates And Cloud! plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 3.7.1 via the fetch_remote_file function. This is due to a filename validation/destination mismatch in fetch_remote_file, where file type validation is performed against the attacker-controlled Content-Disposition filename rather than the URL-path-derived destination filename. This makes it possible for authenticated attackers, with contributor-level access and above, to execute code on the server. A GIF+PHP polyglot file passes wp_check_filetype_and_ext validation as image/gif via the Content-Disposition filename, while the actual destination path is written with a .php extension derived from the URL path, bypassing the unfiltered_upload capability gate entirely. The affected endpoints are reachable at this privilege level because Templately's entire REST API — including the cloud import endpoints used in this attack (/templately/v1/clouds/upload and /templately/v1/insert) — is authorized only by a current_user_can('delete_posts') check, with no administrator or manage_options capability requirement. The same permission gate also allows a contributor to overwrite the site's global Templately cloud connection via the /templately/v1/login endpoint with global_signin set to true. A complete remediation should both correct fetch_remote_file to validate the file type against the actual destination filename rather than the Content-Disposition header (and avoid deriving the write path from the request URL), and restrict state-changing Templately REST routes to an appropriate administrator-level capability.

• RCE
• File upload

Published

Aug 15, 2026

Updated

Aug 20, 2026

EPSS

1.3% · 71th percentile

CWE

CWE-434