CVE-2026-115591

The Contact Form by Supsystic plugin through version 1.10.7 contains a missing authorization vulnerability that allows exploitation of incorrectly configured access control security levels.

The Contact Form by Supsystic WordPress plugin before 1.11.1 does not strip CR/LF characters or re-validate submitted field values before concatenating them into outgoing email headers when a form maps a submitted field to its Reply-To, From, or Cc header. This allows unauthenticated users to inject arbitrary email headers, such as additional Bcc or Cc recipients, into the notification email.

The Contact Form by Supsystic plugin for WordPress is vulnerable to Stored Cross-Site Scripting via IP Address Header in all versions up to, and including, 1.10.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. An unauthenticated attacker can first call the 'updateNonce' action — which is accessible without authentication due to its absence from the plugin's permission list — to obtain a valid nonce, then submit a contact form with a malicious payload in a spoofed IP header such as X-Forwarded-For.

The Contact Form by Supsystic plugin version earlier than 1.10.0 has a bypass vulnerability that does not require authentication. This means an unauthenticated attacker can bypass security mechanisms and gain unauthorized access.

Unauthenticated Cross Site Scripting (XSS) vulnerability in Contact Form by Supsystic versions prior to 1.10.0.