CVE-2026-9309

CVE-2026-9309: Arbitrary JavaScript execution in internal pages via Reader View JSON-LD injection

Published June 1, 2026
Last update June 1, 2026

CVSS base score

What the vulnerability does

Description

Firefox for iOS Reader View did not properly escape HTML tags in JSON-LD metadata. A malicious page could inject markup that changed Reader View behavior and leaked sensitive URL parameters. These parameters could then be used to access internal pages, potentially resulting in arbitrary JavaScript execution in an internal origin. This vulnerability was fixed in Firefox for iOS 151.2.

Key dates

Disclosure timeline

June 1, 2026 CVE published
June 1, 2026 Record updated