CVE-2026-53899
Medium
Description
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.
SeverityMedium
CVSS6.5
Exploit probability—
Product
Mozilla Firefox Mobile
PublishedJun 16, 2026
First seenJun 16, 2026
Weakness typeCWE-345CWE-345
How to fix
Update
- mozilla firefox_mobile152.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox_mobile | v < 152.0 | 152.0 |
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