CVE-2026-12949 Wishlist Member X <= 3.34.1 - Unauthenticated Account Takeover via 'mergewith' Parameter
Unauthenticated attackers can take over any WordPress account, including administrators, by manipulating registration parameters in the Wishlist Member plugin.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-12949?
CVE-2026-12949 is a critical authentication bypass vulnerability in Wishlist Member, published on 14 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The Wishlist Member plugin for WordPress is vulnerable to Account Takeover via Insufficient Verification of Data Authenticity in versions up to and including 3.34.1. This is due to the wpm_register() function validating the registration cookie only against the GET reg parameter while accepting the POST mergewith and POST wpm_id parameters without verifying that the mergewith user ID references a temporary or incomplete registrant that is bound to the current registration transaction. This makes it possible for unauthenticated attackers to take over any existing WordPress account — including administrator accounts — by supplying an arbitrary user's numeric ID as the mergewith value, which causes wp_update_user() to overwrite the target account's username (additionally written via a direct $wpdb UPDATE), password, email address, first name, and last name with attacker-controlled values, while WordPress password and email change notification emails are explicitly suppressed. When wpm_id references a non-existent membership level, no role key is added to the update payload, causing wp_update_user() to preserve the target user's existing role — including administrator — making full privilege escalation a direct consequence of the takeover.
Weakness: CWE-640
Which versions are affected by CVE-2026-12949?
How do I fix CVE-2026-12949?
No fix has been published for CVE-2026-12949 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-12949 being exploited?
There is no known exploitation of CVE-2026-12949 in the wild and no public exploit code.
Sources
Also known as GHSA-xqxv-q9jf-7cwc.