CVE-2026-109705

CRITICAL 9.6

Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component

CVSS Score

9.6

EPSS Score

0.0%

EPSS Percentile

0th

Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.

Vendor	mozilla
Product	firefox
Ecosystems	Browser JavaScript
Industries	Technology
Published	Oct 13, 2026
Last Updated	Oct 13, 2026

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Affected Versions

Mozilla / Firefox

All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗

bugzilla.mozilla.org: https://bugzilla.mozilla.org/show_bug.cgi?id=2040905 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-106/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-108/

Credits

Mozilla