CVE-2026-8840 json
Booking calendar, Appointment Booking System <= 3.2.36 - Missing Authorization to Unauthenticated Arbitrary Modification via wpdevart_payment AJAX Action
published 2026-08-15 2 mo ago modified 2026-08-20 2 mo ago also EUVD-2026-58839
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 46%
- public exploits
- 0
- none known
Summary
The Booking calendar, Appointment Booking System plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 3.2.36. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for unauthenticated attackers to mark arbitrary reservations as paid or completed, cancel legitimate payments, auto-approve reservations, and trigger transactional booking emails by writing attacker-supplied payment status and transaction data directly into the payments table. The auto-approval of reservations is only triggered when the 'enable_psuccess_approval' site option is enabled, but payment status manipulation and email dispatch are exploitable regardless of that setting.
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.55% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
Affected products
- wpdevart Booking calendar, Appointment Booking System
Classification
- Weakness
-
- CWE-862 Missing Authorization
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/88409bb0-5cb0-4f63-b8f0-d72f54fa17b0?source=cve
- plugins.trac.wordpress.org /browser/booking-calendar/tags/3.2.36/admin/controllers/Payment.php#L26
- plugins.trac.wordpress.org /browser/booking-calendar/tags/3.2.36/admin/controllers/Payment.php#L16
- plugins.trac.wordpress.org /browser/booking-calendar/tags/3.2.36/booking_calendar.php#L578
- plugins.trac.wordpress.org /browser/booking-calendar/tags/3.2.36/booking_calendar.php#L131
- plugins.trac.wordpress.org /browser/booking-calendar/tags/3.2.35/admin/controllers/Payment.php#L26
- plugins.trac.wordpress.org /browser/booking-calendar/tags/3.2.35/admin/controllers/Payment.php#L16
- plugins.trac.wordpress.org /browser/booking-calendar/tags/3.2.35/booking_calendar.php#L578
- plugins.trac.wordpress.org /browser/booking-calendar/tags/3.2.35/booking_calendar.php#L131
Sources
- CVE List CVE-2026-8840
- NVD CVE-2026-8840
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.