CVE-2026-86596

s2Member <= 260927 - Unauthenticated Remote Code Execution via 'item_name' IPN Parameter

2026-11-02 08:59
khanhnv

Strategic Overview

Status
Patched in 261001
Affected Plugin
s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions
Affected Version
<= 260927
CVSS
9.8Critical
Weakness type
CWE-94 · Improper Control of Generation of Code
CVE
CVE-2026-86596
View all s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions vulnerabilities

At a glance

CVE-2026-86596 is a critical-severity Improper Control of Generation of Code vulnerability in the s2Member WordPress plugin, affecting versions <= 260927. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 261001; sites on affected versions should update now. Disclosed November 2026, reported by khanhnv.

Vulnerability Overview

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.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-94: Improper Control of Generation of Code

s2Member <= 260927 carries this weakness at item_name, and reaching it takes no account at all. Code injection means input from a request reaches a language construct that evaluates code, so the attacker's text is executed rather than treated as data.

The injected code runs with the web server's privileges, giving the attacker the same access to the database and filesystem as WordPress itself. For s2Member the fix is 261001: builds <= 260927 are affected, anything from 261001 onward is not.

Remediation

Update to version 261001, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: s2Member 261001 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Login Security

External References

https://www.cve.org/CVERecord?id=CVE-2026-86596https://www.wordfence.com/threat-intel/vulnerabilities/id/bbe64cd3-c5ca-4867-90de-4784510a1126https://nvd.nist.gov/vuln/detail/CVE-2026-86596

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C