CVE-2026-15333 is a stored cross-site scripting vulnerability in the Cozy Blocks WordPress plugin, specifically in the 'cozyCustomFont' block attribute. The plugin fails to properly sanitize and escape input, allowing authenticated users with contributor or higher privileges to inject arbitrary web scripts. These scripts execute in the context of any user who views the compromised page, potentially leading to session hijacking or other script-based attacks. The vulnerability affects all versions up to and including 2.2.11. No official patch or remediation guidance has been provided yet.

An attacker with contributor-level access or above can inject persistent malicious scripts into pages via the vulnerable block attribute. These scripts execute in the browsers of users who access the infected pages, potentially leading to theft of sensitive information, session hijacking, or other client-side attacks. The vulnerability does not affect availability but impacts confidentiality and integrity of user sessions and data.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, restrict contributor-level access to trusted users only and consider disabling or removing the Cozy Blocks plugin if possible to prevent exploitation.