CVE-2026-117966

HIGH 8.1CVE-2026-117966 · Published 27/10/2026 · updated 05/11/2026

In short

CVE-2026-117966 is a HIGH (CVSS 8.1) vulnerability.
Chance of exploitation in the next 30 days (EPSS): 0.20%, higher than 10.3% of all vulnerabilities.
No patched version is listed yet: follow the vendor's advisory in References.

Package	Affected versions	Patched versions
—	No affected product versions are listed for this vulnerability yet.

Description

Site isolation issue in the Networking: HTTP component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

References

bugzilla.mozilla.org/show_bug.cgi
mozilla.org/security/advisories/mfsa2026-118
mozilla.org/security/advisories/mfsa2026-119
mozilla.org/security/advisories/mfsa2026-120
mozilla.org/security/advisories/mfsa2026-121
mozilla.org/security/advisories/mfsa2026-122

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