The My Calendar – Accessible Event Manager plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `template` attribute of the `[my_calendar_upcoming]` shortcode in all versions up to, and including, 3.7.3. This is due to the use of `stripcslashes()` on user-supplied shortcode attribute values in the `mc_draw_template()` function, which decodes C-style hex escape sequences (e.g., `\x3c` to `<`) at render time, bypassing WordPress's `wp_kses_post()` content sanitization that runs at save time. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 6
https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.7.2/my-calendar-s…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/my-calendar/tags/3.7.2/my-calendar-t…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/my-calendar/trunk/my-calendar-shortc…
security@wordfence.com
https://plugins.trac.wordpress.org/browser/my-calendar/trunk/my-calendar-templa…
security@wordfence.com
https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&ne…
security@wordfence.com
https://www.wordfence.com/threat-intel/vulnerabilities/id/03d5c82e-f82f-4156-bb…
security@wordfence.com