CVE-2026-115303: Contact Form by Supsystic vulnerability
low 3.7 published 2026-10-29
- Affected versions
- older than 1.11.1
- Fixed in
- 1.11.1
- Latest version
- 1.11.2
- Severity
- Low · CVSS 3.7
- Active installs
- 6,000+
- Type
- Security issue
What an attacker needs
- Access: None. No account or login is needed.
CVSS vector (score by WPScan): CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
What to do now
- Update Contact Form by Supsystic to 1.11.1 or newer (the latest is 1.11.2): Dashboard → Updates, or Plugins → “update now”.
- If you cannot update right away, deactivate it until you can.
- Turn on auto-updates for it: Plugins → “Enable auto-updates” on its row.
- Not sure which version you run? Check your version against every known Contact Form by Supsystic issue.
With WP-CLI:
wp plugin get contact-form-by-supsystic --field=version. - If you ran an affected version and something looks off (new admin users, spam pages, redirects), run the free scan below.
The advisory
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.
References
- NVD CVE-2026-115303 nvd.nist.gov
- WPScan advisory wpscan.com
Related
Ran an affected version? Check your site for signs of a hack
The free scan reads the public side of your site and looks for spam pages, hidden redirects, injected scripts and blacklist entries. No login, no install, about a minute.
Where this data comes from
- CVE record, score and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
- Versions and install counts: wordpress.org/plugins/contact-form-by-supsystic (Plugins API), fetched 2026-11-04.
- The summary, “what an attacker needs” and “what to do” sections are our plain-English reading of the record and the plugin's release history; the quoted description is the record's own text. Spot an error? Email Daniel.