CVE-2026-16387criticalCWE-200CWE-284CWE-346

CVE-2026-16387: critical vulnerability in Mozilla Firefox

Site isolation issue in the Networking component

Published · Updated

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28Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 9.8epss 0.3%
Site isolation issue in the Networking component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
Mozilla · FirefoxMozilla · Thunderbird
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