CVE-2026-4698
critical
CVSS v3
9.8
CVSS v4 NEW
—
VIR risk
9.8
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.
Predictions
Exploit likelihood
97%
Patch ETA
—
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Mitigation details
Source: Red Hat Errata — Red Hat Inc. · View original ↗ · Open-Errata-API
Description firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component Red Hat statement Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory. CVSS v3: 7.5 (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H) Errata / fixed releases ProductPackageAdvisoryReleased Red Hat Enterprise Linux…
Description
firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component
Red Hat statement
Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
CVSS v3: 7.5 (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H)
Errata / fixed releases
| Product | Package | Advisory | Released |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | firefox-0:140.9.0-1.el10_1 | RHSA-2026:5931 | 2026-03-26T00:00:00Z |
| Red Hat Enterprise Linux 10 | thunderbird-0:140.9.0-1.el10_1 | RHSA-2026:6342 | 2026-04-01T00:00:00Z |
| Red Hat Enterprise Linux 10.0 Extended Update Support | firefox-0:140.9.0-1.el10_0 | RHSA-2026:7843 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 10.0 Extended Update Support | thunderbird-0:140.9.0-1.el10_0 | RHSA-2026:8315 | 2026-04-15T00:00:00Z |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | firefox-0:140.9.0-1.el7_9 | RHSA-2026:8427 | 2026-04-16T00:00:00Z |
| Red Hat Enterprise Linux 8 | firefox-0:140.9.0-1.el8_10 | RHSA-2026:5932 | 2026-03-26T00:00:00Z |
| Red Hat Enterprise Linux 8 | thunderbird-0:140.9.0-1.el8_10 | RHSA-2026:6917 | 2026-04-07T00:00:00Z |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | firefox-0:140.9.0-1.el8_2 | RHSA-2026:7840 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | thunderbird-0:140.9.0-1.el8_2 | RHSA-2026:8285 | 2026-04-15T00:00:00Z |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | firefox-0:140.9.0-1.el8_4 | RHSA-2026:7858 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | thunderbird-0:140.9.0-1.el8_4 | RHSA-2026:8850 | 2026-04-20T00:00:00Z |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | firefox-0:140.9.0-1.el8_4 | RHSA-2026:7858 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | thunderbird-0:140.9.0-1.el8_4 | RHSA-2026:8850 | 2026-04-20T00:00:00Z |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | firefox-0:140.9.0-1.el8_6 | RHSA-2026:7842 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | thunderbird-0:140.9.0-1.el8_6 | RHSA-2026:8289 | 2026-04-15T00:00:00Z |
| Red Hat Enterprise Linux 8.6 Telecommunications Update Service | firefox-0:140.9.0-1.el8_6 | RHSA-2026:7842 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 8.6 Telecommunications Update Service | thunderbird-0:140.9.0-1.el8_6 | RHSA-2026:8289 | 2026-04-15T00:00:00Z |
| Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions | firefox-0:140.9.0-1.el8_6 | RHSA-2026:7842 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions | thunderbird-0:140.9.0-1.el8_6 | RHSA-2026:8289 | 2026-04-15T00:00:00Z |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | firefox-0:140.9.0-1.el8_8 | RHSA-2026:7838 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | thunderbird-0:140.9.0-1.el8_8 | RHSA-2026:8288 | 2026-04-15T00:00:00Z |
| Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | firefox-0:140.9.0-1.el8_8 | RHSA-2026:7838 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | thunderbird-0:140.9.0-1.el8_8 | RHSA-2026:8288 | 2026-04-15T00:00:00Z |
| Red Hat Enterprise Linux 9 | firefox-0:140.9.0-1.el9_7 | RHSA-2026:5930 | 2026-03-26T00:00:00Z |
| Red Hat Enterprise Linux 9 | thunderbird-0:140.9.0-1.el9_7 | RHSA-2026:6188 | 2026-03-30T00:00:00Z |
| Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | firefox-0:140.9.0-1.el9_0 | RHSA-2026:7839 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | thunderbird-0:140.9.0-1.el9_0 | RHSA-2026:8286 | 2026-04-15T00:00:00Z |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | firefox-0:140.9.0-1.el9_2 | RHSA-2026:7841 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | thunderbird-0:140.9.0-1.el9_2 | RHSA-2026:8287 | 2026-04-15T00:00:00Z |
| Red Hat Enterprise Linux 9.4 Extended Update Support | firefox-0:140.9.0-1.el9_4 | RHSA-2026:7845 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 9.4 Extended Update Support | thunderbird-0:140.9.0-1.el9_4 | RHSA-2026:8290 | 2026-04-15T00:00:00Z |
| Red Hat Enterprise Linux 9.6 Extended Update Support | firefox-0:140.9.0-1.el9_6 | RHSA-2026:7837 | 2026-04-13T00:00:00Z |
| Red Hat Enterprise Linux 9.6 Extended Update Support | thunderbird-0:140.9.0-1.el9_6 | RHSA-2026:8284 | 2026-04-15T00:00:00Z |
Package state
| Product | Package | State |
|---|---|---|
| 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 |
Apply commands
Apply RHSA-2026:5931 for Red Hat Enterprise Linux 10
yum update -y firefox
# or:
dnf upgrade -y firefoxAffected
| Vendor | Product | Version |
|---|---|---|
| redhat | Red Hat Enterprise Linux 10 | Affected |
| redhat | Red Hat Enterprise Linux 10 | Affected |
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 140.9.0esr-1~deb13u1 |
| sid | Fixed | 149.0-1 |
| forky | Fixed | 140.9.0esr-1 |
| bullseye | Fixed | 140.9.0esr-1~deb11u1 |
| bookworm | Fixed | 140.9.0esr-1~deb12u1 |
Red Hat Fixed 2 releases
| Version | Status | Fixed in |
|---|---|---|
| 9 | Fixed | — |
| 8 | Fixed | — |
Rocky Linux Fixed 2 releases
| Version | Status | Fixed in |
|---|---|---|
| 9 | Fixed | — |
| 8 | Fixed | — |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| mozilla | firefox | {"endExcluding":"115.34.0"} | 115.34.0 |
References
- https://errata.rockylinux.org/RLSA-2026:5932
- https://access.redhat.com/errata/RHSA-2026:5930
- https://access.redhat.com/errata/RHSA-2026:6188
- https://bugzilla.mozilla.org/show_bug.cgi?id=2020906
- https://www.mozilla.org/security/advisories/mfsa2026-20/
- https://www.mozilla.org/security/advisories/mfsa2026-21/
- https://www.mozilla.org/security/advisories/mfsa2026-22/
- https://www.mozilla.org/security/advisories/mfsa2026-23/
- https://www.mozilla.org/security/advisories/mfsa2026-24/
- https://security-tracker.debian.org/tracker/CVE-2026-4698
- https://errata.rockylinux.org/RLSA-2026:6188
- https://errata.rockylinux.org/RLSA-2026:5930
- https://www.suse.com/security/cve/CVE-2026-4698.html
- https://access.redhat.com/errata/RHSA-2026:5932
- https://bugzilla.redhat.com/2450710
- https://bugzilla.redhat.com/2450711
- https://bugzilla.redhat.com/2450712
- https://bugzilla.redhat.com/2450713
- https://bugzilla.redhat.com/2450714
- https://bugzilla.redhat.com/2450715
- https://bugzilla.redhat.com/2450718
- https://bugzilla.redhat.com/2450719
- https://bugzilla.redhat.com/2450720
- https://bugzilla.redhat.com/2450721
- https://bugzilla.redhat.com/2450722
CWEs
CWE-843
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.