Paper/Archive/CVE-2026-109705

CVE-2026-109705

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

EPSS 0.3%CVSS 9.6

critical.is priorityof 100

CVSS 9.6 (ADP)9.6 / 10 × 3028.8 Not in CISA KEV+300.0 EPSS percentile 25.5.255 × 205.1 No public exploit+100.0 SSVC exploitation: none+100.0

Description · from the CVE record

Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird 153.5, and Firefox ESR 115.44.

Affected

ProductAffectedFixed inSource

Firefoxsee advisory115.44CNA

Thunderbirdsee advisory153.5CNA

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=2040905 refmozilla.org/security/advisories/mfsa2026-106 refmozilla.org/security/advisories/mfsa2026-108 refmozilla.org/security/advisories/mfsa2026-109 refmozilla.org/security/advisories/mfsa2026-110 refmozilla.org/security/advisories/mfsa2026-119