Sandbox escape in the DOM: Core & HTML component
Published Sep 15, 2026
9.6
CRITICALCVSS 3.1
EPSS 0.35%
Description
Sandbox escape in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
Affected products
No data.
No data.
No data.
Red Hat Enterprise Linux 10
firefox-0:140.16.0-1.el10_2
Fixed · RHSA-2026:69461
Red Hat Enterprise Linux 9
firefox-0:140.16.0-1.el9_8
Fixed · RHSA-2026:69462
Red Hat Enterprise Linux 10
rhel10/firefox-flatpak
Affected
Red Hat Enterprise Linux 10
rhel10/thunderbird-flatpak
Affected
Red Hat Enterprise Linux 10
thunderbird
Affected
Red Hat Enterprise Linux 6
firefox
Out of support scope
Red Hat Enterprise Linux 6
thunderbird
Out of support scope
Red Hat Enterprise Linux 7
firefox
Affected
Red Hat Enterprise Linux 7
thunderbird
Out of support scope
Red Hat Enterprise Linux 8
firefox
Affected
Red Hat Enterprise Linux 8
thunderbird
Affected
Red Hat Enterprise Linux 9
thunderbird
Affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | firefox-0:140.16.0-1.el10_2 | Fixed | RHSA-2026:69461 |
| Red Hat Enterprise Linux 9 | firefox-0:140.16.0-1.el9_8 | Fixed | RHSA-2026:69462 |
| Red Hat Enterprise Linux 10 | rhel10/firefox-flatpak | Affected | n/a |
| Red Hat Enterprise Linux 10 | rhel10/thunderbird-flatpak | Affected | n/a |
| Red Hat Enterprise Linux 10 | thunderbird | Affected | n/a |
| Red Hat Enterprise Linux 6 | firefox | Out of support scope | n/a |
| Red Hat Enterprise Linux 6 | thunderbird | Out of support scope | n/a |
| Red Hat Enterprise Linux 7 | firefox | Affected | n/a |
| Red Hat Enterprise Linux 7 | thunderbird | Out of support scope | n/a |
| Red Hat Enterprise Linux 8 | firefox | Affected | n/a |
| Red Hat Enterprise Linux 8 | thunderbird | Affected | n/a |
| Red Hat Enterprise Linux 9 | thunderbird | 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:U/C:H/I:H/A:H
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 20, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 3, 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 3, 2026 | 0.35% (0.00350) | 26.37th | v5 (v2026.06.15) |
| Sep 16, 2026 | 0.16% (0.00156) | 5.18th | v5 (v2026.06.15) |
References (14)
- https://access.redhat.com/security/cve/CVE-2026-92018 Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=2064287
- https://bugzilla.redhat.com/show_bug.cgi?id=2533773 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2026-92018
- https://www.cve.org/CVERecord?id=CVE-2026-92018
- https://www.mozilla.org/security/advisories/mfsa2026-90/
- https://www.mozilla.org/security/advisories/mfsa2026-91/
- https://www.mozilla.org/security/advisories/mfsa2026-92/
- https://www.mozilla.org/security/advisories/mfsa2026-92/#CVE-2026-92018
- https://www.mozilla.org/security/advisories/mfsa2026-93/
- https://www.mozilla.org/security/advisories/mfsa2026-94/
- https://www.mozilla.org/security/advisories/mfsa2026-95/
- https://www.mozilla.org/security/advisories/mfsa2026-95/#CVE-2026-92018
- https://www.mozilla.org/security/advisories/mfsa2026-96/
Change history (0)
No recorded changes yet.