Description
Site isolation issue in the Networking component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
Affected products
mozilla: firefox; mozilla: thunderbird
References5
- www.mozilla.org/security/advisories/mfsa2026-68/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-70/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-71/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-72/ Vendor Advisory
- bugzilla.mozilla.org/show_bug.cgi?id=2043200 Permissions Required
Metrics
- CVSS 3.1
-
9.8
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 10 · as of 14 November 2026
- CWE
- CWE-200CWE-284CWE-346
Could this be exploited in your environment?
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