WordPressプラグイン「Import and export users and customers」に不適切な権限の割り当ての脆弱性（CVE-2026-86583）

The Import and export users and customers plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 2.4.17 via the plugin's own export and re-import workflow. The vulnerability exists because the exporter writes CSV cells using fputcsv() with a NUL byte (\0) as the escape character, while the importer parses the same file using SplFileObject::fgetcsv() with only a single delimiter argument, causing PHP's default backslash escape character to be applied instead; because the export column layout places display_name immediately before the role column and nickname immediately after, an attacker can store crafted values in those two profile fields — saved by WordPress core via the standard profile page — such that the escape mismatch causes the parser to merge the display_name cell into the role field and rebalance the column count via nickname, yielding administrator as the parsed role for their own row when it reaches the import_user function's add_role function. This makes it possible for authenticated attackers with Subscriber-level access or above to escalate their privileges to Administrator. Exploitation requires a site administrator to trigger the plugin's documented export re-import migration with both "Update existing users" and "Update roles for existing users" set to "yes".