CVE-2026-74986criticalCWE-200

CVE-2026-74986: critical vulnerability in Mozilla Firefox

Site isolation issue in the CSS Parsing and Computation component

Published · Updated

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28Vexday Risk Score

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

ssvc Trackcvss 9.1epss 0.6%
Site isolation issue in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Affected products
Mozilla · FirefoxMozilla · Thunderbird
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