Medium 5.4Published Jun 1, 2026

CVE-2026-9308Arbitrary JavaScript execution in Reader View due to wrong HTML replacement order

Updated under an hour ago (Oct 26, 2026, 6:00 AM ET)

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It affects Mozilla Firefox for iOS and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for Mozilla Firefox for iOS

Exploited in the last 30 days

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.

CVSS: 5.4 MEDIUM (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: mozilla
NVD analysis: Analyzed
Record last updated: Jun 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Mozilla Firefox for iOS mozilla:firefox_for_ios (from the name)	from 151.2 not affected	CNA record
mozilla firefox mozilla:firefox	before 151.2	NVD

References

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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.