CVE-2026-18496

Booking Calendar <= 11.4.3 - Unauthenticated Sensitive Information Exposure in 'WPBC_FLEXTIMELINE_NAV' AJAX Action

2026-10-09 17:02
Jonah Burgess (CryptoCat)

Strategic Overview

Status
Patched in 11.5
Affected Plugin
Booking Calendar
Affected Version
<= 11.4.3
CVSS
5.3Medium
Weakness type
CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor
CVE
CVE-2026-18496
View all Booking Calendar vulnerabilities

At a glance

CVE-2026-18496 is a medium-severity Exposure of Sensitive Information to an Unauthorized Actor vulnerability in the Booking Calendar WordPress plugin, affecting versions <= 11.4.3. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 11.5; sites on affected versions should update now. Disclosed October 2026, reported by Jonah Burgess (CryptoCat).

Vulnerability Overview

The Booking Calendar plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 11.4.3 via the wpbc_is_show_popover_in_flex_timeline() function. This makes it possible for unauthenticated attackers to extract sensitive data including names, email addresses, and phone numbers of customers who have made bookings.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

Booking Calendar <= 11.4.3 carries this weakness at wpbc_is_show_popover_in_flex_timeline(), and reaching it takes no account at all. Sensitive information exposure means data the application intended to keep internal is returned to a caller who should not be able to see it.

The disclosed data — credentials, tokens, customer records or internal paths — is usually worth more as material for a follow-up attack than as an end in itself. For Booking Calendar the fix is 11.5: builds <= 11.4.3 are affected, anything from 11.5 onward is not.

Remediation

Update to version 11.5, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: Booking Calendar 11.5 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-18496https://www.wordfence.com/threat-intel/vulnerabilities/id/1ebfb030-c9b7-477a-8fe3-78e97da6bea9https://nvd.nist.gov/vuln/detail/CVE-2026-18496

Related records

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