CVE-2026-9309

5.4 MEDIUM 0.2% exploit odds Fix listed XSS Browser & mail

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in, but needs a user to act. Limited direct impact.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-01 13:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-07-22 07:10 UTC Last updatedMost recent change to the record

Details

Published: 2026-06-01 13:16 UTC
Last modified: 2026-07-22 07:10 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-79 · Cross-site scripting
Record status: Analyzed

Affected

Mozilla Firefox < 151.2

Attack profile CVSS 3.1 · 5.4

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

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Fix and advisories

https://www.mozilla.org/security/advisories/mfsa2026-53/

References

NVD record · CVE.org record