CVE-2026-9308

MEDIUM 5.4

Arbitrary JavaScript execution in Reader View due to wrong HTML replacement order

CVSS Score

5.4

EPSS Score

0.0%

EPSS Percentile

0th

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.

Vendor	mozilla
Product	firefox for ios
Ecosystems	Browser JavaScript
Industries	Technology
Published	Jun 1, 2026
Last Updated	Jun 1, 2026

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Affected Versions

Mozilla / Firefox for iOS

All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗

bugzilla.mozilla.org: https://bugzilla.mozilla.org/show_bug.cgi?id=2039422 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-53/

Credits

Muneaki Nishimura