CVE intelligence and bounded remediation

CVE-2026-3906 — WordPress core is vulnerable to unauthorized access in versions 6.9 through 6.9.1

Medium CVSS 4.3

WordPress core is vulnerable to unauthorized access in versions 6.9 through 6.9.1. The Notes feature (block-level collaboration annotations) was introduced in WordPress 6.9 to allow editorial comments directly on posts in the block editor. However, the REST API `create_item_permissions_check()` method in the comments controller did not verify that the authenticated user has `edit_post` permission on the target post when creating a note. This makes it possible for authenticated attackers with Subscriber-level access to create notes on any post, including posts authored by other users, private posts, and posts in any status.

Severity
Medium
CVSS
4.3 (3.1)
Published
2026-03-11
CISA KEV
Not currently listed
Ecosystem
php/wordpress
Weaknesses
CWE-862

Affected products

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Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

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Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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