CVE-2026-109740CWE-119

CVE-2026-109740

Critical · published October 13, 2026

CVSS v3.1
9.6
EPSS
0%
Percentile
27.3
In the wild
Unconfirmed
What it is

Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

The record
Technical detail
CVSS v3.1
9.6 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00349 · 27.3th percentile
Weakness
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer
Published
2026-10-13T17:17Z
References (5)
https://bugzilla.mozilla.org/show_bug.cgi?id=2057113 · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-106/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-108/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-109/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-110/ · [email protected]
EPSS history
Timeline
  • 15 OCT 03:28Z
    EPSS moved — → 0%
    epss
  • 13 OCT 12:29Z
    Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component
    cvelistv5
  • 13 OCT 12:29Z
    Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component
    cvelistv5