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CVE-2026-103883

HIGHCVSS 8.8/10EPSS 0.71%

Last modified

CVE-2026-103883 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. 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. EPSS estimates a 0.71% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.71%

54.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-103883?
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.
How severe is CVE-2026-103883?
CVE-2026-103883 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.71% probability of exploitation in the next 30 days.
How do I fix CVE-2026-103883?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST