CVE-2026-14556: Happyforms vulnerability
medium 5.4 published 2026-10-21
- Affected versions
- older than 1.26.15
- Fixed in
- 1.26.15
- Latest version
- 1.26.17
- Severity
- Medium · CVSS 5.4
- Active installs
- 20,000+
- Type
- Security issue
What an attacker needs
- Access: None. No account or login is needed.
- Interaction: It also needs someone on the site (often an admin) to click a link, open a page or submit a form the attacker prepared.
CVSS vector (score by WPScan): CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
What to do now
- Update Happyforms to 1.26.15 or newer (the latest is 1.26.17): 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 Happyforms issue.
With WP-CLI:
wp plugin get happyforms --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 HappyForms WordPress plugin before 1.26.15 does not sanitise or escape a user-controlled referral value before embedding it in the form notification email, allowing unauthenticated attackers to inject arbitrary HTML into the emails site administrators receive.
References
- NVD CVE-2026-14556 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/happyforms (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.