Review reviewCritical
CVE-2026-16387
Mozilla Firefox, Thunderbird, firefox
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
- 9.8
- EPSS
- 0.20% 10.6% percentile
- CISA KEV
- Not listed
- Published
- 2026.07.21