CVE-2026-91831: Subscribe to Comments vulnerability
low 3.8 published 2026-10-19
- Affected versions
- 2.3 up to (not including) 2.3.3
- Fixed in
- 2.3.3
- Latest version
- 2.3.3
- Severity
- Low · CVSS 3.8
- Active installs
- 10,000+
- Type
- Security issue
What an attacker needs
- Access: A logged-in account with Author-level access or higher.
CVSS vector (score by WPScan): CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N
What to do now
- Update Subscribe to Comments to 2.3.3 or newer: 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 Subscribe to Comments issue.
With WP-CLI:
wp plugin get subscribe-to-comments --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 Subscribe to Comments WordPress plugin before 2.3.3 does not sanitise newline characters from a notification sender-name setting before using it in e-mail headers, allowing users with Author-level access and above to inject arbitrary e-mail headers, such as a hidden Bcc, and to spoof the sender.
References
- NVD CVE-2026-91831 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/subscribe-to-comments (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.