CVE-2026-12626: Online Scheduling and Appointment Booking System PHP object injection vulnerability

high 7.2 published 2026-10-10 · updated 2026-10-13

Affected versions: 28.2 and older
Fixed in: 28.3 *
Latest version: 28.7
Severity: High · CVSS 7.2
Active installs: 60,000+
Type: PHP object injection

* The source does not name a fixed version; this is the first wordpress.org release after the last affected version.

What an attacker needs

Access: A logged-in account with Custom-level access or higher.

CVSS vector (score by Wordfence): CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

What to do now

Update Online Scheduling and Appointment Booking System to 28.3 or newer (the latest is 28.7): 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 Online Scheduling and Appointment Booking System issue. With WP-CLI: wp plugin get bookly-responsive-appointment-booking-tool --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 Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 28.2 via deserialization of untrusted input via the ‘value’ parameter. This makes it possible for authenticated attackers, with custom-level access and above, to inject a PHP Object. No known gadget chain is available.

Description from the CVE record, published by Wordfence (the CVE Numbering Authority), via the NVD entry for CVE-2026-12626.

References

NVD CVE-2026-12626 nvd.nist.gov
Wordfence advisory www.wordfence.com
Code change (fix) plugins.trac.wordpress.org

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/bookly-responsive-appointment-booking-tool (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.