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 is configured to map a submitted field into its Reply-To, From or Cc header, allowing unauthenticated users to inject arbitrary email headers such as additional Bcc or Cc recipients into the notification email.
CVE-2026-115303
CVSS base score
3.7 (v3.1)
Severity
LOW
Attack vector
Network
Weakness
CWE-93
Last modified
October 29, 2026
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N