CyberSecBulletin
CVE-2026-15303NVD status: Deferred

6Storage Rentals: Improper Authentication

Published Updated By the CyberSecBulletin desk

CVE-2026-15303 is a critical-severity improper authentication vulnerability in 6Storage Rentals from Sixstorage, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected 6Storage Rentals versions: 2.27.0 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.84% chance of exploitation within 30 days, higher than 59% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of 6Storage Rentals you run against the affected versions below, and install the vendor's latest release.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Sixstorage6Storage Rentals2.27.0 and earlierNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (wordfence.com).

Official description

The 6Storage Rentals plugin for WordPress is vulnerable to authentication bypass in versions up to, and including, 2.27.0. This is due to the six_storage_create_wp_user() AJAX handler being registered on wp_ajax_nopriv_six_storage_create_wp_user without any nonce, capability, credential, or ownership verification, while calling wp_set_current_user() and wp_set_auth_cookie() for any WordPress user resolved by the attacker-supplied email address. This makes it possible for unauthenticated attackers to log in as any existing WordPress user, including administrators, by submitting that user's email address.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

How developers prevent this class of flaw

  • Use an authentication framework or library such as the OWASP ESAPI Authentication feature.

More Improper Authentication vulnerabilities (CWE-287)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in 6Storage Rentals

All 6Storage Rentals vulnerabilities

Recent Improper Authentication vulnerabilities

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