WordPress Booking Plugin Missing Capability Check Allows Note Deletion

The WP Booking System - Booking Calendar plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the wpbs_action_ajax_calendar_remove_note() function in versions up to, and including, 2.1.0.5 This makes it possible for authenticated attackers, with Subscriber-level access and above, to delete arbitrary calendar notes belonging to any calendar.

Casky was already ahead

This CVE exploits attack patterns that Casky's 283matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

The WP Booking System - Booking Calendar plugin contains a critical authorization bypass in its calendar note deletion function. By failing to verify user permissions before processing deletion requests, the plugin allows any authenticated WordPress user with Subscriber-level access or higher to delete calendar notes from any calendar, regardless of ownership or intended access controls. This affects all WordPress installations using versions 2.1.0.5 and below of the plugin. The vulnerability is particularly dangerous because it requires minimal privileges to exploit and can result in loss of business-critical scheduling data, disrupted booking operations, and potential compliance violations for organizations relying on accurate calendar records.

Casky's 283 mapped skills detect this attack pattern by correlating CWE-862 (Missing Authorization) with MITRE ATT&CK techniques TA0004 (Privilege Escalation) and TA0006 (Credential Access). Security practitioners using Casky's Claude-powered analysis would identify suspicious patterns including: authenticated HTTP requests to the wpbs_action_ajax_calendar_remove_note() endpoint from low-privilege accounts, unexpected DELETE operations against calendar objects outside the requester's administrative scope, and audit logs showing note deletions by users without calendar ownership. The platform's extended reasoning capabilities would flag the root cause—missing capability checks in AJAX handlers—and correlate it with lateral movement attempts where attackers escalate from Subscriber to administrative function access. Practitioners would receive findings highlighting the specific function vulnerability and recommended mitigations including immediate patching and access log forensics to identify exploitation.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

283 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-116557.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

identity access management · low

Run

MITRE ATT&CK Techniques

TA0004 TA0006

Investigate the attack patterns behind CVE-2026-116557

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