The Wp Social Login and Register Social Counter plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Avatar Alt Attribute via Arbitrary User Meta Write in all versions up to, and including, 3.2.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the attacker to chain two steps: invoking the nonce-only dismiss_ajax_call endpoint (nonce accessible to Subscribers via any wp-admin page) to set the xs_social_profile_image meta flag on their own account, which activates the unescaped img output branch in xs_social_get_avatar, and then setting their display name to a script payload that core's ENT_NOQUOTES handling preserves unescaped.
Attack Parameters
Impact Assessment
CVSS Vector v3.1