CVE-2026-16387

Weakness

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

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=2043200
• https://www.mozilla.org/security/advisories/mfsa2026-68/
• https://www.mozilla.org/security/advisories/mfsa2026-70/
• https://www.mozilla.org/security/advisories/mfsa2026-71/
• https://www.mozilla.org/security/advisories/mfsa2026-72/