CVE-2026-3367

MEDIUM
Published Jul 11, 2026 Modified Jul 13, 2026 CWE-79

Description

The Lockme OAuth2 calendars integration plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'App ID' setting in all versions up to, and including, 2.11.0. This is due to insufficient input sanitization and output escaping. The register_setting() call on line 197 lacks a sanitize callback, allowing unsanitized data to be stored via update_option(). When the settings page is rendered, the stored value is echoed directly into an HTML input's value attribute without esc_attr() on line 212. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary web scripts in the settings page that will execute whenever a user accesses the plugin settings page. Multiple fields are affected: App ID (client_id), App Secret (client_secret), Bookings ID prefix (id_prefix), and API domain (api_domain). This vulnerability is particularly impactful in WordPress multisite installations where administrators of individual sites should not be able to execute JavaScript affecting other users.

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CVSS v3.1 Score

4.4
MEDIUM
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0026
Probability of exploitation
0.17%
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

https://plugins.trac.wordpress.org/browser/lockme-calendars-integration/tags/2.9.3/src/Plugin.php#L197 https://plugins.trac.wordpress.org/browser/lockme-calendars-integration/tags/2.9.3/src/Plugin.php#L212 https://plugins.trac.wordpress.org/browser/lockme-calendars-integration/tags/2.9.3/src/Plugin.php#L223 https://plugins.trac.wordpress.org/browser/lockme-calendars-integration/tags/2.9.3/src/Plugin.php#L245 https://plugins.trac.wordpress.org/browser/lockme-calendars-integration/tags/2.9.3/src/Plugin.php#L256 https://plugins.trac.wordpress.org/browser/lockme-calendars-integration/tags/2.9.3/src/Plugin.php#L54 https://plugins.trac.wordpress.org/browser/lockme-calendars-integration/trunk/src/Plugin.php#L197 https://plugins.trac.wordpress.org/browser/lockme-calendars-integration/trunk/src/Plugin.php#L212 https://plugins.trac.wordpress.org/browser/lockme-calendars-integration/trunk/src/Plugin.php#L223 https://plugins.trac.wordpress.org/browser/lockme-calendars-integration/trunk/src/Plugin.php#L245

Frequently Asked Questions

What is CVE-2026-3367? +
The Lockme OAuth2 calendars integration plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'App ID' setting in all versions up to, and including, 2.11.0. This is due to insufficient input sanitization and output escaping. The register_setting() call on line 197 lacks a sanitize callback, allowing unsanitized data to be stored via update_option(). When the settings page is rendered, the stored value is echoed directly into an HTML input's value attribute without esc_attr() on line 212. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary web scripts in the settings page that will execute whenever a user accesses the plugin settings page. Multiple fields are affected: App ID (client_id), App Secret (client_secret), Bookings ID prefix (id_prefix), and API domain (api_domain). This vulnerability is particularly impactful in WordPress multisite installations where administrators of individual sites should not be able to execute JavaScript affecting other users. It has a CVSS v3.1 base score of 4.4 (MEDIUM).
How severe is CVE-2026-3367? +
CVE-2026-3367 has a CVSS v3.1 score of 4.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0026, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-3367? +
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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