A HIGH-severity vulnerability identified as CVE-2026-1321 has been published on March 5, 2026 with a CVSS base score of 8.1. This security advisory provides a detailed breakdown of the vulnerability, its potential impact, weakness classification, and actionable steps to protect your systems.
Vulnerability Details
CVE ID: CVE-2026-1321
Severity: HIGH
CVSS Score: 8.1
Published: March 5, 2026
Weakness (CWE): CWE-862
| Attack Vector | Network |
| Attack Complexity | High |
| Privileges Required | None |
| User Interaction | None |
| Confidentiality Impact | High |
| Integrity Impact | High |
| Availability Impact | High |
Technical Description
The Membership Plugin – Restrict Content plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 3.2.20. This is due to the `rcp_setup_registration_init()` function accepting any membership level ID via the `rcp_level` POST parameter without validating that the level is active or that payment is required. Combined with the `add_user_role()` method which assigns the WordPress role configured on the membership level without status checks, this makes it possible for unauthenticated attackers to register with any membership level, including inactive levels that grant privileged WordPress roles such as Administrator, or paid levels that charge a sign-up fee. The vulnerability was partially patched in version 3.2.18.
Potential Impact
If exploited, this high-severity vulnerability could allow an attacker to compromise sensitive data confidentiality, tamper with system integrity, cause a denial of service. Organizations running affected software should treat this as a priority remediation item.
Recommended Action
No official patch is available yet. Until one is released:
- Monitor the official NVD page and vendor channels for patch announcements.
- Restrict access to the affected system or service where possible.
- Apply network-level mitigations such as firewall rules or WAF policies.
- Enable logging and alerting for anomalous activity related to this vulnerability.
- Review your incident response plan in case of active exploitation.
References
Related Security Advisories
- [HIGH] CVE-2026-1876 — CVSS 8.7 (March 3, 2026) — HIGH / CVSS 8.7
- [HIGH] CVE-2026-20423 — CVSS 7.1 (March 2, 2026) — HIGH / CVSS 7.1
- [HIGH] CVE-2026-20416 — CVSS 7.2 (March 2, 2026) — HIGH / CVSS 7.2
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