CVE-2026-5436

Description

The MW WP Form plugin for WordPress is vulnerable to Arbitrary File Move/Read in all versions up to and including 5.1.1. This is due to insufficient validation of the $name parameter (upload field key) passed to the generate_user_file_dirpath() function, which uses WordPress's path_join() — a function that returns absolute paths unchanged, discarding the intended base directory. The attacker-controlled key is injected via the mwf_upload_files[] POST parameter, which is loaded into the plugin's Data model via _set_request_valiables(). During form processing, regenerate_upload_file_keys() iterates over these keys and calls generate_user_filepath() with the attacker-supplied key as the $name argument — the key survives validation because the targeted file (e.g., wp-config.php) genuinely exists at the absolute path. The _get_attachments() method then re-reads the same surviving keys and passes the resolved file path to move_temp_file_to_upload_dir(), which calls rename() to move the file into the uploads folder. This makes it possible for unauthenticated attackers to move arbitrary files on the server, which can easily lead to remote code execution when the right file is moved (such as wp-config.php). The vulnerability is only exploitable if a file upload field is added to the form and the “Saving inquiry data in database” option is enabled.

Gravité et risque d'exploitation

CVE-2026-5436 obtient un score CVSS de 8.1/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.92 %, ce qui la place devant 59.8 % des CVE référencées.

Que faire ?

• Vérifiez si MW WP Form (versions 0, <=5.1.1) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://www.wordfence.com/threat-intel/vulnerabilities/id/bc308993-7fc5-41db-a396-f05e95fe47b8?source=cve
• https://plugins.trac.wordpress.org/browser/mw-wp-form/tags/5.1.1/classes/models/class.directory.php#L138
• https://plugins.trac.wordpress.org/browser/mw-wp-form/tags/5.1.1/classes/models/class.data.php#L591
• https://plugins.trac.wordpress.org/changeset/3501261/mw-wp-form
• https://github.com/web-soudan/mw-wp-form/commit/f872ab18ca670f5867b2241745daa30cd0fab861