# Quick PayPal Payments: Payment Button & Form <= 6.0.4 - Unauthenticated Reflected Cross-Site Scripting via 'form' Parameter

- **ID:** WPSEC-2026-1103
- **Plugin:** Quick PayPal Payments: Payment Button & Form (`quick-paypal-payments`), https://wordpress.org/plugins/quick-paypal-payments/
- **Affected versions:** from 5.7.51 before 6.0.5
- **Fixed in:** 6.0.5 (Update to 6.0.5 or later.)
- **Severity:** Medium 6.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)
- **Weakness:** CWE-79
- **Usage among sites WPSec scans:** plugin Low, affected versions None seen (as of 2026-10-16)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/quick-paypal-payments
- **Fix released:** 2026-10-14
- **Published:** 2026-10-16
- **URL:** https://wpsec.com/vuln/WPSEC-2026-1103/

## Description

The Quick PayPal Payments: Payment Button & Form plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'form' URL parameter in versions 5.7.51 up to, and including, 6.0.4 due to insufficient input sanitization and output escaping. On a page with a [qpp] shortcode that names no form, the parameter's value was passed only through sanitize_text_field, which keeps quotes, and was then written into an inline script. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

## References

- https://wpsec.com/vuln/WPSEC-2026-1103/
- https://plugins.svn.wordpress.org/quick-paypal-payments/tags/6.0.5/
- https://wordpress.org/plugins/quick-paypal-payments/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-1103/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.