Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component
Published Sep 15, 2026
9.6
CRITICALCVSS 3.1
EPSS 0.26%
Description
Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.
Affected products
No data.
No data.
No data.
Red Hat Enterprise Linux 10
firefox
Not affected
Red Hat Enterprise Linux 10
rhel10/firefox-flatpak
Not affected
Red Hat Enterprise Linux 10
rhel10/thunderbird-flatpak
Not affected
Red Hat Enterprise Linux 10
thunderbird
Not affected
Red Hat Enterprise Linux 6
firefox
Not affected
Red Hat Enterprise Linux 6
thunderbird
Not affected
Red Hat Enterprise Linux 7
firefox
Not affected
Red Hat Enterprise Linux 7
thunderbird
Not affected
Red Hat Enterprise Linux 8
firefox
Not affected
Red Hat Enterprise Linux 8
thunderbird
Not affected
Red Hat Enterprise Linux 9
firefox
Not affected
Red Hat Enterprise Linux 9
thunderbird
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 10 | rhel10/firefox-flatpak | Not affected | n/a |
| Red Hat Enterprise Linux 10 | rhel10/thunderbird-flatpak | Not affected | n/a |
| Red Hat Enterprise Linux 10 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 6 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 6 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 7 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 7 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 8 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 8 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 9 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 9 | thunderbird | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
1 other source (Red Hat) ▾
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
NoTechnical Impact
TotalDecision
n/aAssessed Sep 22, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
Sep–Oct 2026- EPSS v5
Percentile over time
- EPSS v5
Table of values (2 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.26% (0.00255) | 15.48th | v5 (v2026.06.15) |
| Sep 16, 2026 | 0.14% (0.00144) | 4.02th | v5 (v2026.06.15) |
References (11)
- https://access.redhat.com/security/cve/CVE-2026-92071 Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=2061231
- https://bugzilla.redhat.com/show_bug.cgi?id=2533733 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2026-92071
- https://www.cve.org/CVERecord?id=CVE-2026-92071
- https://www.mozilla.org/security/advisories/mfsa2026-90/
- https://www.mozilla.org/security/advisories/mfsa2026-90/#CVE-2026-92071
- https://www.mozilla.org/security/advisories/mfsa2026-93/
- https://www.mozilla.org/security/advisories/mfsa2026-94/
- https://www.mozilla.org/security/advisories/mfsa2026-94/#CVE-2026-92071
- https://www.mozilla.org/security/advisories/mfsa2026-96/
Change history (0)
No recorded changes yet.