Medium 5.4Published Jun 1, 2026

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

Updated under an hour ago (Oct 26, 2026, 9:50 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 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.

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=2036573permissions-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.