CVE-2026-103883sixstorage 6Storage Rentals improper authentication

What it is

The software does not prove who a caller is, so an attacker can pass as someone else.

How it is reached

An attacker can exploit it over the network, with an ordinary user account, and nobody has to click anything.

What an attacker gains

A successful attack can read the data it protects, change data or behaviour and take it offline. In practice, this kind of flaw lets an attacker act as a signed-in user, or an administrator, without valid credentials.

Is it being exploited?

There is no public report of exploitation yet.

What to do

1. No fixed version is listed yet. Find every place sixstorage 6Storage Rentals runs, watch the references for a fix, and plan a replacement if it is no longer supported.
2. While there is no fix, review who holds accounts that can reach it.

Description from NVD

The 6Storage Rentals plugin for WordPress is vulnerable to Authentication Bypass leading to Administrator Account Takeover in all versions up to, and including, 2.31.0. The vulnerability exists because the `six_storage_portal_registration()` AJAX handler — registered on `wp_ajax_six_storage_portal_plugin_registration` — performs no capability check and no nonce verification before writing the caller-supplied `six_storage_online_api_url` POST parameter to the site-wide option of the same name; the unauthenticated `six_storage_create_wp_user()` handler then redeems a transient seeded from that attacker-controlled URL's response and unconditionally calls `wp_set_current_user()` and `wp_set_auth_cookie()` with no ownership or credential verification. This makes it possible for authenticated attackers, with Subscriber-level access and above, to authenticate as any existing WordPress user — including any administrator whose email address is known or guessable — resulting in full site compromise. This issue represents an incomplete fix for a prior vulnerability: the 2.29.0 remediation moved the target email out of POST data into a server-side transient, but because any Subscriber can still overwrite the outbound API URL that populates that transient, the full authentication bypass chain remains exploitable in three AJAX requests.