by Kastro
Paper/Archive/CVE-2026-100819

CVE-2026-100819

Mozilla Firefox — Sandbox escape due to incorrect boundary conditions in the XPCOM component

EPSS 0.3%CVSS 9.6
critical.is priorityof 100
33
CVSS 9.6 (ADP)9.6 / 10 × 3028.8Not in CISA KEV+300.0EPSS percentile 18.3.183 × 203.7No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

Affected

ProductAffectedFixed inSource
Firefoxsee advisory115.42CNA
Thunderbirdsee advisory140.17CNA

Scores by source

CISA ADP9.6CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

refbugzilla.mozilla.org/show_bug.cgi?id=2071069refmozilla.org/security/advisories/mfsa2026-100refmozilla.org/security/advisories/mfsa2026-101refmozilla.org/security/advisories/mfsa2026-102refmozilla.org/security/advisories/mfsa2026-103refmozilla.org/security/advisories/mfsa2026-97refmozilla.org/security/advisories/mfsa2026-98refmozilla.org/security/advisories/mfsa2026-99