CVE-2026-100819

CRITICAL 9.6

Sandbox escape due to incorrect boundary conditions in the XPCOM component

CVSS Score

9.6

EPSS Score

0.0%

EPSS Percentile

0th

Sandbox escape due to incorrect boundary conditions in the XPCOM component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

Vendor	mozilla
Product	firefox
Ecosystems	Browser JavaScript
Industries	Technology
Published	Sep 29, 2026
Last Updated	Sep 29, 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=2071069 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-100/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-97/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-98/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-99/

Credits

Mozilla