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CVE-2026-103883: WordPress 6Storage Rentals Improper Authentication Vulnerability

CVE-2026-103883 explained: high Improper Authentication in WordPress 6Storage Rentals. CVSS 8.8. Affected versions, detection, fixes and CTEM priority.

Last updated: Nov 11, 2026

CVSS
8.8 HIGH
EPSS
n/a
CISA KEV
Not listed
CWE
CWE-287

Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS

CVE-2026-103883 Overview

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.

Critical Impact

Remote, authenticated attackers can exploit this Improper Authentication in WordPress 6Storage Rentals. The CVSS base score is 8.8 (High).

Affected Products

  • WordPress 6Storage Rentals: see the vendor advisory for the exact affected versions

Discovery Timeline

  • 2026-11-11: CVE-2026-103883 published to the National Vulnerability Database by security@wordfence.com
  • 2026-11-11: last updated in the NVD database

Technical Details for CVE-2026-103883

Vulnerability Analysis

CVE-2026-103883 is a Improper Authentication weakness (CWE-287: Improper Authentication) in WordPress 6Storage Rentals. Based on its CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction. The software does not properly prove who a user is.

With a CVSS base score of 8.8, apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Root Cause

The weakness is classified as CWE-287: Improper Authentication. The software does not properly prove who a user is.

Attack Vector

Based on the CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction. Attack complexity is low complexity.

No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.

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

Detection Methods for CVE-2026-103883

Detection Strategies

  • Inventory every instance of WordPress 6Storage Rentals and compare the running version with the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Run an authenticated vulnerability scan once your scanner ships a check for this CVE.

Monitoring Recommendations

  • Forward WordPress 6Storage Rentals application, access and audit logs to your SIEM for retrospective hunting.
  • Alert on new processes, configuration changes or outbound connections from the affected service.
  • Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.

How to Mitigate CVE-2026-103883

Immediate Actions Required

  • Apply the fixed version of WordPress 6Storage Rentals named in the vendor advisory.
  • Prioritize internet facing and business critical instances first.
  • Rescan after the change to confirm the exposure is closed.

Patch Information

Use the fixed version listed in the vendor advisory for WordPress 6Storage Rentals.

Workarounds

  • If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.

CWE References

Technical References

This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.

Frequently asked questions

CVE-2026-103883 is a high severity Improper Authentication in WordPress 6Storage Rentals with a CVSS score of 8.8. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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