Vulnerability in Mozilla Firefox For Ios
CVE-2026-53899
Firefox for iOS used partial domain matching when attaching cookies to PDF requests, allowing a malicious site on a suffix domain to receive cookies belonging to the target site. This vulnerability was fixed in Firefox for iOS 152.0.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.
Affected products
- Mozilla Firefox For Ios — versions 152.0
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-53899?
- CVE-2026-53899 is a medium-severity vulnerability in Mozilla Firefox For Ios, classified under Insufficient Verification of Data Authenticity. CVSS score: 6.5/10. Published 2026-06-16.
- How severe is CVE-2026-53899?
- Medium severity. CVSS v3 base score is 6.5 out of 10.