Simple Membership <= 4.3.4 - Privilege escalation via Registration
Strategic Overview
- Status
- Patched in 4.3.5
- Affected Plugin
- Simple Membership
- Affected Version
<= 4.3.4- CVSS
- 7.3High
- Weakness type
- CWE-20 · Improper Input Validation
- CVE
CVE-2023-41957
At a glance
CVE-2023-41957 is a high-severity Improper Input Validation vulnerability in the Simple Membership WordPress plugin, affecting versions <= 4.3.4. It carries a CVSS score of 7.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 4.3.5; sites on affected versions should update now. Disclosed September 2023, reported by Rafie Muhammad.
Vulnerability Overview
The Simple Membership plugin for WordPress is vulnerable to privilege escalation due to missing input validation on the create_swpm_user function in versions up to, and including, 4.3.4. This makes it possible for unauthenticated attackers to register users with arbitrary membership levels. Since membership levels can be granted a higher user role than subscriber, this can lead to privilege escalation
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.
CWE-20: Improper Input Validation
Reaching this weakness in Simple Membership <= 4.3.4 takes a caller who can reach the endpoint. Improper input validation means the application accepts input without confirming it has the form, type or range the code downstream assumes.
The concrete impact depends on where the unvalidated value lands, which is why records in this class range from cosmetic bugs to full compromise. For Simple Membership the fix is 4.3.5: builds <= 4.3.4 are affected, anything from 4.3.5 onward is not.
Remediation
Update to version 4.3.5, or a newer patched version
How does WordSec protect against this?
The attempt arrives as an ordinary request to Simple Membership: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Simple Membership 4.3.5 closes this, and updating the plugin is the step that ends it.
- Firewall
- Alerts
External References
Related records
Same weakness class
Other vulnerabilities in Simple Membership
- 9.8CVE-2022-2317: Simple Membership Membership Privilege Escalation
CVE-2022-2317 - 8.8CVE-2022-2273: Simple Membership Membership Privilege Escalation
CVE-2022-2273 - 8.8CVE-2022-0328: Simple Membership CSRF to Arbitrary Member Deletion
CVE-2022-0328 - 8.8CVE-2019-14328: Simple Membership <= 3.8.4 Cross-Site Request Forgery
CVE-2019-14328 - 8.8CVE-2016-10884: Simple Membership <= 3.3.2 Multiple CSRF
CVE-2016-10884 - 7.2CVE-2026-15931: Simple Membership <= 4.7.7 Stored Cross-Site Scripting
CVE-2026-15931 - 7.2CVE-2026-42663: Simple Membership <= 4.7.2 Stored Cross-Site Scripting
CVE-2026-42663 - 7.2CVE-2023-4719: Simple Membership <= 4.3.5 Reflected XSS
CVE-2023-4719
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