JIT miscompilation in the JavaScript Engine: JIT component
Published Mar 24, 2026
9.8
CRITICALCVSS 3.1
EPSS 0.76%
Description
JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Affected products
No data.
No data.
Red Hat Enterprise Linux 10
firefox-0:140.9.0-1.el10_1
Fixed · RHSA-2026:5931
Red Hat Enterprise Linux 10
thunderbird-0:140.9.0-1.el10_1
Fixed · RHSA-2026:6342
Red Hat Enterprise Linux 10.0 Extended Update Support
firefox-0:140.9.0-1.el10_0
Fixed · RHSA-2026:7843
Red Hat Enterprise Linux 10.0 Extended Update Support
thunderbird-0:140.9.0-1.el10_0
Fixed · RHSA-2026:8315
Red Hat Enterprise Linux 7 Extended Lifecycle Support
firefox-0:140.9.0-1.el7_9
Fixed · RHSA-2026:8427
Red Hat Enterprise Linux 8
firefox-0:140.9.0-1.el8_10
Fixed · RHSA-2026:5932
Red Hat Enterprise Linux 8
thunderbird-0:140.9.0-1.el8_10
Fixed · RHSA-2026:6917
Red Hat Enterprise Linux 8.2 Advanced Update Support
firefox-0:140.9.0-1.el8_2
Fixed · RHSA-2026:7840
Red Hat Enterprise Linux 8.2 Advanced Update Support
thunderbird-0:140.9.0-1.el8_2
Fixed · RHSA-2026:8285
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
firefox-0:140.9.0-1.el8_4
Fixed · RHSA-2026:7858
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
thunderbird-0:140.9.0-1.el8_4
Fixed · RHSA-2026:8850
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
firefox-0:140.9.0-1.el8_4
Fixed · RHSA-2026:7858
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
thunderbird-0:140.9.0-1.el8_4
Fixed · RHSA-2026:8850
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
firefox-0:140.9.0-1.el8_6
Fixed · RHSA-2026:7842
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
thunderbird-0:140.9.0-1.el8_6
Fixed · RHSA-2026:8289
Red Hat Enterprise Linux 8.6 Telecommunications Update Service
firefox-0:140.9.0-1.el8_6
Fixed · RHSA-2026:7842
Red Hat Enterprise Linux 8.6 Telecommunications Update Service
thunderbird-0:140.9.0-1.el8_6
Fixed · RHSA-2026:8289
Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
firefox-0:140.9.0-1.el8_6
Fixed · RHSA-2026:7842
Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
thunderbird-0:140.9.0-1.el8_6
Fixed · RHSA-2026:8289
Red Hat Enterprise Linux 8.8 Telecommunications Update Service
firefox-0:140.9.0-1.el8_8
Fixed · RHSA-2026:7838
Red Hat Enterprise Linux 8.8 Telecommunications Update Service
thunderbird-0:140.9.0-1.el8_8
Fixed · RHSA-2026:8288
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
firefox-0:140.9.0-1.el8_8
Fixed · RHSA-2026:7838
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
thunderbird-0:140.9.0-1.el8_8
Fixed · RHSA-2026:8288
Red Hat Enterprise Linux 9
firefox-0:140.9.0-1.el9_7
Fixed · RHSA-2026:5930
Red Hat Enterprise Linux 9
thunderbird-0:140.9.0-1.el9_7
Fixed · RHSA-2026:6188
Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions
firefox-0:140.9.0-1.el9_0
Fixed · RHSA-2026:7839
Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions
thunderbird-0:140.9.0-1.el9_0
Fixed · RHSA-2026:8286
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
firefox-0:140.9.0-1.el9_2
Fixed · RHSA-2026:7841
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
thunderbird-0:140.9.0-1.el9_2
Fixed · RHSA-2026:8287
Red Hat Enterprise Linux 9.4 Extended Update Support
firefox-0:140.9.0-1.el9_4
Fixed · RHSA-2026:7845
Red Hat Enterprise Linux 9.4 Extended Update Support
thunderbird-0:140.9.0-1.el9_4
Fixed · RHSA-2026:8290
Red Hat Enterprise Linux 9.6 Extended Update Support
firefox-0:140.9.0-1.el9_6
Fixed · RHSA-2026:7837
Red Hat Enterprise Linux 9.6 Extended Update Support
thunderbird-0:140.9.0-1.el9_6
Fixed · RHSA-2026:8284
Red Hat Enterprise Linux 10
rhel10/firefox-flatpak
Affected
Red Hat Enterprise Linux 10
rhel10/thunderbird-flatpak
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
thunderbird
Out of support scope
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | firefox-0:140.9.0-1.el10_1 | Fixed | RHSA-2026:5931 |
| Red Hat Enterprise Linux 10 | thunderbird-0:140.9.0-1.el10_1 | Fixed | RHSA-2026:6342 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | firefox-0:140.9.0-1.el10_0 | Fixed | RHSA-2026:7843 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | thunderbird-0:140.9.0-1.el10_0 | Fixed | RHSA-2026:8315 |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | firefox-0:140.9.0-1.el7_9 | Fixed | RHSA-2026:8427 |
| Red Hat Enterprise Linux 8 | firefox-0:140.9.0-1.el8_10 | Fixed | RHSA-2026:5932 |
| Red Hat Enterprise Linux 8 | thunderbird-0:140.9.0-1.el8_10 | Fixed | RHSA-2026:6917 |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | firefox-0:140.9.0-1.el8_2 | Fixed | RHSA-2026:7840 |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | thunderbird-0:140.9.0-1.el8_2 | Fixed | RHSA-2026:8285 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | firefox-0:140.9.0-1.el8_4 | Fixed | RHSA-2026:7858 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | thunderbird-0:140.9.0-1.el8_4 | Fixed | RHSA-2026:8850 |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | firefox-0:140.9.0-1.el8_4 | Fixed | RHSA-2026:7858 |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | thunderbird-0:140.9.0-1.el8_4 | Fixed | RHSA-2026:8850 |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | firefox-0:140.9.0-1.el8_6 | Fixed | RHSA-2026:7842 |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | thunderbird-0:140.9.0-1.el8_6 | Fixed | RHSA-2026:8289 |
| Red Hat Enterprise Linux 8.6 Telecommunications Update Service | firefox-0:140.9.0-1.el8_6 | Fixed | RHSA-2026:7842 |
| Red Hat Enterprise Linux 8.6 Telecommunications Update Service | thunderbird-0:140.9.0-1.el8_6 | Fixed | RHSA-2026:8289 |
| Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions | firefox-0:140.9.0-1.el8_6 | Fixed | RHSA-2026:7842 |
| Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions | thunderbird-0:140.9.0-1.el8_6 | Fixed | RHSA-2026:8289 |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | firefox-0:140.9.0-1.el8_8 | Fixed | RHSA-2026:7838 |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | thunderbird-0:140.9.0-1.el8_8 | Fixed | RHSA-2026:8288 |
| Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | firefox-0:140.9.0-1.el8_8 | Fixed | RHSA-2026:7838 |
| Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | thunderbird-0:140.9.0-1.el8_8 | Fixed | RHSA-2026:8288 |
| Red Hat Enterprise Linux 9 | firefox-0:140.9.0-1.el9_7 | Fixed | RHSA-2026:5930 |
| Red Hat Enterprise Linux 9 | thunderbird-0:140.9.0-1.el9_7 | Fixed | RHSA-2026:6188 |
| Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | firefox-0:140.9.0-1.el9_0 | Fixed | RHSA-2026:7839 |
| Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | thunderbird-0:140.9.0-1.el9_0 | Fixed | RHSA-2026:8286 |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | firefox-0:140.9.0-1.el9_2 | Fixed | RHSA-2026:7841 |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | thunderbird-0:140.9.0-1.el9_2 | Fixed | RHSA-2026:8287 |
| Red Hat Enterprise Linux 9.4 Extended Update Support | firefox-0:140.9.0-1.el9_4 | Fixed | RHSA-2026:7845 |
| Red Hat Enterprise Linux 9.4 Extended Update Support | thunderbird-0:140.9.0-1.el9_4 | Fixed | RHSA-2026:8290 |
| Red Hat Enterprise Linux 9.6 Extended Update Support | firefox-0:140.9.0-1.el9_6 | Fixed | RHSA-2026:7837 |
| Red Hat Enterprise Linux 9.6 Extended Update Support | thunderbird-0:140.9.0-1.el9_6 | Fixed | RHSA-2026:8284 |
| 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 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 | thunderbird | Out of support scope | 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:N/S:U/C:H/I:H/A:H
2 other sources (CISA ADP, Red Hat) ▾
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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 May 22, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.
Score over time
Mar–Oct 2026- EPSS v4
- EPSS v5
Percentile over time
- EPSS v4
- EPSS v5
Table of values (3 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 2, 2026 | 0.76% (0.00755) | 53.50th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.60% (0.00603) | 43.98th | v5 (v2026.06.15) |
| Mar 25, 2026 | 0.02% (0.00020) | 5.41th | v4 (v2025.03.14) |
References (38)
- https://access.redhat.com/errata/RHSA-2026:5930
- https://access.redhat.com/errata/RHSA-2026:5931
- https://access.redhat.com/errata/RHSA-2026:5932
- https://access.redhat.com/errata/RHSA-2026:6188
- https://access.redhat.com/errata/RHSA-2026:6342
- https://access.redhat.com/errata/RHSA-2026:6917
- https://access.redhat.com/errata/RHSA-2026:7837
- https://access.redhat.com/errata/RHSA-2026:7838
- https://access.redhat.com/errata/RHSA-2026:7839
- https://access.redhat.com/errata/RHSA-2026:7840
- https://access.redhat.com/errata/RHSA-2026:7841
- https://access.redhat.com/errata/RHSA-2026:7842
- https://access.redhat.com/errata/RHSA-2026:7843
- https://access.redhat.com/errata/RHSA-2026:7845
- https://access.redhat.com/errata/RHSA-2026:7858
- https://access.redhat.com/errata/RHSA-2026:8284
- https://access.redhat.com/errata/RHSA-2026:8285
- https://access.redhat.com/errata/RHSA-2026:8286
- https://access.redhat.com/errata/RHSA-2026:8287
- https://access.redhat.com/errata/RHSA-2026:8288
- https://access.redhat.com/errata/RHSA-2026:8289
- https://access.redhat.com/errata/RHSA-2026:8290
- https://access.redhat.com/errata/RHSA-2026:8315
- https://access.redhat.com/errata/RHSA-2026:8427
- https://access.redhat.com/errata/RHSA-2026:8850
- https://access.redhat.com/security/cve/CVE-2026-4698 Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=2020906 Permissions Required
- https://bugzilla.redhat.com/show_bug.cgi?id=2450719 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2026-4698
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4698.json
- https://www.cve.org/CVERecord?id=CVE-2026-4698
- https://www.mozilla.org/security/advisories/mfsa2026-20/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-21/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-22/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-22/#CVE-2026-4698
- https://www.mozilla.org/security/advisories/mfsa2026-23/
- https://www.mozilla.org/security/advisories/mfsa2026-24/
- https://www.mozilla.org/security/advisories/mfsa2026-24/#CVE-2026-4698
Change history (0)
No recorded changes yet.