CVE-2026-6286: XSS (CVSS 7.2)

Description

The Booking for Appointments and Events Calendar – Amelia plugin for WordPress is vulnerable to Stored Cross-Site Scripting via customer name fields in versions up to and including 2.2. This is due to an authentication bypass where the AddBookingCommand explicitly skips nonce verification (Command.php line 186), allowing unauthenticated users to submit booking data. While the plugin applies sanitize_text_field() to customer firstName and lastName fields (BookingApplicationService.php lines 302-308), this function only removes HTML tags and preserves special characters including double quotes. The vulnerability manifests in the administrative Calendar view where a FullCalendar eventContent callback interpolates customer names directly into JavaScript template literals (redesign/dist/index.js line 199) and renders them via innerHTML without proper HTML entity encoding. Because double quotes are preserved, an attacker can inject payloads like '" onmouseover="alert(document.cookie)"' to break out of the title attribute and inject malicious event handlers. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that will execute when an administrator accesses the Calendar page and hovers over the malicious appointment.

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CVSS v3.1 Score

7.2

HIGH

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

EPSS — Exploit Prediction

0.0044

Probability of exploitation

0.38%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

Frequently Asked Questions

What is CVE-2026-6286? +

The Booking for Appointments and Events Calendar – Amelia plugin for WordPress is vulnerable to Stored Cross-Site Scripting via customer name fields in versions up to and including 2.2. This is due to an authentication bypass where the AddBookingCommand explicitly skips nonce verification (Command.php line 186), allowing unauthenticated users to submit booking data. While the plugin applies sanitize_text_field() to customer firstName and lastName fields (BookingApplicationService.php lines 302-308), this function only removes HTML tags and preserves special characters including double quotes. The vulnerability manifests in the administrative Calendar view where a FullCalendar eventContent callback interpolates customer names directly into JavaScript template literals (redesign/dist/index.js line 199) and renders them via innerHTML without proper HTML entity encoding. Because double quotes are preserved, an attacker can inject payloads like '" onmouseover="alert(document.cookie)"' to break out of the title attribute and inject malicious event handlers. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that will execute when an administrator accesses the Calendar page and hovers over the malicious appointment. It has a CVSS v3.1 base score of 7.2 (HIGH).

How severe is CVE-2026-6286? +

CVE-2026-6286 has a CVSS v3.1 score of 7.2 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0044, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-6286? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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