CVE-2026-8955
Description
Important: thunderbird security update
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Mitigation details
Description firefox: thunderbird: Privilege escalation in the DOM: Workers component Red Hat statement Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory. CVSS v3: 6.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N) Errata / fixed releases ProductPackageAdvisoryReleased Red Hat Enterprise Linux…
Description
firefox: thunderbird: Privilege escalation in the DOM: Workers component
Red Hat statement
Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
CVSS v3: 6.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)
Errata / fixed releases
| Product | Package | Advisory | Released |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | firefox-0:140.11.0-1.el10_2 | RHSA-2026:21380 | 2026-05-27T00:00:00Z |
| Red Hat Enterprise Linux 10 | thunderbird-0:140.11.0-1.el10_2 | RHSA-2026:22325 | 2026-06-01T00:00:00Z |
| Red Hat Enterprise Linux 8 | firefox-0:140.11.0-1.el8_10 | RHSA-2026:21382 | 2026-05-27T00:00:00Z |
| Red Hat Enterprise Linux 9 | firefox-0:140.11.0-1.el9_8 | RHSA-2026:21378 | 2026-05-27T00:00:00Z |
| Red Hat Enterprise Linux 9 | thunderbird-0:140.11.0-1.el9_8 | RHSA-2026:21381 | 2026-05-27T00:00:00Z |
Package state
| Product | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 10 | rhel10/thunderbird-flatpak | Affected |
| Red Hat Enterprise Linux 6 | thunderbird | Out of support scope |
| Red Hat Enterprise Linux 7 | thunderbird | Out of support scope |
Apply commands
yum update -y firefox
# or:
dnf upgrade -y firefoxAffected
| Vendor | Product | Version |
|---|---|---|
| redhat | Red Hat Enterprise Linux 10 | Affected |
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
AlmaLinux Fixed 2 releases
| Version | Status | Fixed in |
|---|---|---|
| 9 | Fixed | firefox-x11-140.11.0-1.el9_8.alma.1.ppc64le.rpm |
| 8 | Fixed | firefox-140.11.0-1.el8_10.alma.1.aarch64.rpm |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 140.11.0esr-1~deb13u1 |
| sid | Fixed | 151.0-1 |
| forky | Fixed | 140.11.0esr-1 |
| bullseye | Fixed | 140.11.0esr-1~deb11u1 |
| bookworm | Fixed | 140.11.0esr-1~deb12u1 |
Red Hat Fixed 2 releases
| Version | Status | Fixed in |
|---|---|---|
| 9 | Fixed | — |
| 8 | Fixed | — |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| mozilla | firefox | {"endExcluding":"140.11.0"} | 140.11.0 |
| mozilla | thunderbird | {"endExcluding":"140.11"} | 140.11 |
References
- https://access.redhat.com/errata/RHSA-2026:21381
- https://bugzilla.mozilla.org/show_bug.cgi?id=2031064
- https://www.mozilla.org/security/advisories/mfsa2026-46/
- https://www.mozilla.org/security/advisories/mfsa2026-48/
- https://www.mozilla.org/security/advisories/mfsa2026-50/
- https://www.mozilla.org/security/advisories/mfsa2026-51/
- https://security-tracker.debian.org/tracker/CVE-2026-8955
- https://www.suse.com/security/cve/CVE-2026-8955.html
- https://access.redhat.com/errata/RHSA-2026:21378
- https://access.redhat.com/errata/RHSA-2026:21382
- https://bugzilla.redhat.com/2476469
- https://bugzilla.redhat.com/2476475
- https://bugzilla.redhat.com/2476492
- https://bugzilla.redhat.com/2479839
- https://bugzilla.redhat.com/2479840
- https://bugzilla.redhat.com/2479842
- https://bugzilla.redhat.com/2479846
- https://bugzilla.redhat.com/2479847
- https://bugzilla.redhat.com/2479848
- https://bugzilla.redhat.com/2479849
- https://bugzilla.redhat.com/2479852
- https://bugzilla.redhat.com/2479853
- https://bugzilla.redhat.com/2479855
- https://bugzilla.redhat.com/2479860
- https://bugzilla.redhat.com/2479871
CWEs
CWE-269
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.