CVE-2026-59558

Booking Calendar <= 11.4.2 - Unauthenticated Stored Cross-Site Scripting

2026-07-27 00:00

Strategic Overview

Status: Patched in 11.4.3
Affected Plugin: Booking Calendar
Affected Version: <= 11.4.2
CVSS: 7.2High
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2026-59558

View all Booking Calendar vulnerabilities

At a glance

CVE-2026-59558 is a high-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Booking Calendar WordPress plugin, affecting versions <= 11.4.2. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 11.4.3; sites on affected versions should update now. Disclosed July 2026, reported by daroo.

Vulnerability Overview

The Booking Calendar plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to, and including, 11.4.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

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-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Reaching this weakness in Booking Calendar <= 11.4.2 takes no account at all. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Booking Calendar the fix is 11.4.3: builds <= 11.4.2 are affected, anything from 11.4.3 onward is not.

Remediation

Update to version 11.4.3, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Booking Calendar 11.4.3 closes this, and updating the plugin is the step that ends it.

Firewall
Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-59558 https://www.wordfence.com/threat-intel/vulnerabilities/id/73809551-b925-4789-b059-b9e60743f693 https://nvd.nist.gov/vuln/detail/CVE-2026-59558

Related records

Same weakness class

Other vulnerabilities in Booking Calendar

CVSS Vector

7.2

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

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