CVE-2026-9308: Firefox iOS Reader View Templating flaw -> arbitrary JS exec before 151.2
CVE-2026-9308 Published on June 1, 2026
Arbitrary JavaScript execution in Reader View due to wrong HTML replacement order
Firefox for iOS Reader View replaced page content in its HTML template before replacing other internal placeholders. A malicious page could include a placeholder string that was later substituted with JSON-LD data, potentially resulting in arbitrary JavaScript execution. This vulnerability was fixed in Firefox for iOS 151.2.
Vulnerability Analysis
CVE-2026-9308 is exploitable with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.
Weakness Type
What is a XSS Vulnerability?
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CVE-2026-9308 has been classified to as a XSS vulnerability or weakness.
Products Associated with CVE-2026-9308
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Affected Versions
Mozilla Firefox for iOS:- Version 151.2, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.