The Otter Blocks plugin for WordPress suffers from a stored cross-site scripting vulnerability due to improper neutralization of input during web page generation. Specifically, user-supplied attributes like 'id' in the plugin's widgets are not properly sanitized or escaped, allowing authenticated users with contributor or higher privileges to inject arbitrary JavaScript code. This code executes in the context of any user who views the compromised page, potentially leading to session hijacking or other client-side attacks. The vulnerability affects all versions up to 2.6.5. The CVSS 3.1 base score is 6.4, reflecting network attack vector, low attack complexity, required privileges at the contributor level, no user interaction, and impacts on confidentiality and integrity with no availability impact.

An attacker with contributor-level or higher access can inject persistent malicious scripts into pages via the vulnerable plugin widgets. These scripts execute in the browsers of users who visit the infected pages, potentially compromising user sessions or performing unauthorized actions within the context of the affected site. The impact is limited to confidentiality and integrity, with no direct impact on availability. There are no known exploits in the wild at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict contributor-level access to trusted users only and consider disabling or removing the Otter Blocks plugin if possible. Monitor for updates from the vendor (themeisle) regarding patches or official fixes.