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MEDIUM · 6.5

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 wa...

Vulnerability 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.

CVSS Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE

Affected Products

VendorProductVersions
MozillaFirefox Mobile< 152.0

Related Weaknesses (CWE)

CWE-345

References

FAQ

What is CVE-2026-53899?

CVE-2026-53899 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 wa...

How severe is CVE-2026-53899?

CVE-2026-53899 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-53899?

Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox Mobile.