CVE-2026-15984 QuickCal <= 1.0.20 - Unauthenticated Stored Cross-Site Scripting via Custom Field Parameters
Unauthenticated attackers can inject arbitrary scripts via custom fields in QuickCal, leading to code execution or account takeover when users view affected pages.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-15984?
CVE-2026-15984 is a high-severity cross-site scripting vulnerability in Themovation QuickCal, published on 5 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The QuickCal plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Custom Field Parameters in all versions up to, and including, 1.0.20 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. The nonce guarding the unauthenticated booked_add_appt AJAX action is publicly embedded on any page rendering the booking calendar shortcode, making it trivially obtainable by unauthenticated attackers without any prior account or privilege.
Weakness: CWE-79
Which versions are affected by CVE-2026-15984?
How do I fix CVE-2026-15984?
No fix has been published for CVE-2026-15984 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-15984 being exploited?
There is no known exploitation of CVE-2026-15984 in the wild and no public exploit code.
Sources
Also known as GHSA-3566-c9r4-mj76.