CVE-2026-8840Booking calendar, Appointment Booking System <= 3.2.36 - Missing Authorization to Unauthenticated Arbitrary Modification via wpdevart_payment AJAX Action
- 5.3MediumCVSS base score
- 0.55%Exploitation in 30 daysEPSS · top 54% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By Wordfence
- 3 months later
· 3 months later
Published
- 2 days later
· 2 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| WordfenceCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| NVDNVD · Deferred | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.55% · top 54% of all CVEs (15 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Affected products
wpdevart · Booking calendar, Appointment Booking System
- affected ≤ 3.2.36
References
References9
- https://www.wordfence.com/threat-intel/vulnerabilities/id/88409bb0-5cb0-4f63-b8f0-d72f54fa17b0?source=cve (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.36/admin/controllers/Payment.php#L26 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.36/admin/controllers/Payment.php#L16 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.36/booking_calendar.php#L578 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.36/booking_calendar.php#L131 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.35/admin/controllers/Payment.php#L26 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.35/admin/controllers/Payment.php#L16 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.35/booking_calendar.php#L578 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.35/booking_calendar.php#L131 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-58839 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-8840)Record last updated .