CVE-2026-5436
Published: 08 April 2026
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…
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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.
Mitigating Controls (NIST 800-53 r5)AI
Requires validation of the attacker-controlled $name parameter in mwf_upload_files[] to block path traversal via absolute paths in generate_user_file_dirpath().
Mandates timely remediation of the flaw in MW WP Form plugin versions up to 5.1.1 through patching as detailed in advisories and GitHub commits.
Restricts information inputs like mwf_upload_files[] to whitelisted valid upload field keys, preventing injection of arbitrary absolute paths.
Security SummaryAI
CVE-2026-5436 is an arbitrary file move and read vulnerability in the MW WP Form plugin for WordPress, affecting all versions up to and including 5.1.1. The issue stems from insufficient validation of the attacker-controlled $name parameter, which is the upload field key passed via the mwf_upload_files[] POST parameter. This parameter is loaded into the plugin's Data model and processed during form handling. Specifically, the generate_user_file_dirpath() function relies on WordPress's path_join(), which fails to enforce the intended base directory and preserves absolute paths. As a result, an attacker-supplied key referencing an existing file like wp-config.php survives validation and enables unauthorized file operations.
Unauthenticated attackers can exploit this vulnerability remotely by submitting a malicious form submission, provided the target form includes a file upload field and the "Saving inquiry data in database" option is enabled. During processing, functions like regenerate_upload_file_keys() and _get_attachments() use the tainted key to resolve absolute paths, passing them to move_temp_file_to_upload_dir(), which invokes rename() to relocate the file into the uploads directory. This allows attackers to move sensitive files such as wp-config.php, potentially leading to remote code execution, with a CVSS v3.1 base score of 8.1 (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H) and mapping to CWE-22 (Path Traversal).
Mitigation details are available in referenced advisories and patches, including a GitHub commit (f872ab18ca670f5867b2241745daa30cd0fab861) that addresses the validation flaw, WordPress plugin trac changesets (e.g., 3501261), and source code locations in class.data.php and class.directory.php. Security teams should update to a patched version of the MW WP Form plugin beyond 5.1.1, as detailed in the Wordfence threat intelligence report.
Details
- CWE(s)
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability allows unauthenticated remote exploitation of a public-facing WordPress plugin via path traversal for arbitrary file move and read, directly mapping to T1190: Exploit Public-Facing Application.