CVE-2026-6771
published 2026-04-21CVE-2026-6771: Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
PriorityP353critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
0.31%
22.9th percentile
Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Affected
9 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 150 | Firefox 150 |
| mozilla | firefox | < 150.0 | 150.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 140.0 < 140.10.0 | 140.10.0 |
| mozilla | firefox_esr | < Firefox ESR 140.10 | Firefox ESR 140.10 |
| mozilla | thunderbird | < Thunderbird 140.10 | Thunderbird 140.10 |
| mozilla | thunderbird | < Thunderbird 150 | Thunderbird 150 |
| mozilla | thunderbird | >= 140.0 < 140.10.0 | 140.10.0 |
| rhel10 | firefox-flatpak | — | — |
CVSS provenance
nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vendor_redhat9.8CRITICAL
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Red Hat
firefox: Mitigation bypass in the DOM: Security component
vendor_redhat·2026-04-21·CVSS 9.8
CVE-2026-6771 [CRITICAL] CWE-358 firefox: Mitigation bypass in the DOM: Security component
firefox: Mitigation bypass in the DOM: Security component
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
Mitigation bypass in the DOM: Security component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: firefox (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: firefox (Red Hat Enterprise Linux 6) - Out of support scope
Package: firefox (Red Hat Enterprise Linux 7) - Affected
Package: firefox (Red Hat Enterprise Linux 8) - Affected
Package: firefox (Red Hat Enterprise Linux 9) - Affected
Mozilla
Mozilla Foundation Security Advisory 2026-32: CVE-2026-6771
vendor_mozilla·CVSS 9.8
CVE-2026-6771 [CRITICAL] Mozilla Foundation Security Advisory 2026-32: CVE-2026-6771
Mozilla Foundation Security Advisory 2026-32
CVE: CVE-2026-6771
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.10
Mozilla
Mozilla Foundation Security Advisory 2026-34: CVE-2026-6771
vendor_mozilla·CVSS 9.8
CVE-2026-6771 [CRITICAL] Mozilla Foundation Security Advisory 2026-34: CVE-2026-6771
Mozilla Foundation Security Advisory 2026-34
CVE: CVE-2026-6771
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.10
Mozilla
Mozilla Foundation Security Advisory 2026-30: CVE-2026-6771
vendor_mozilla·CVSS 9.8
CVE-2026-6771 [CRITICAL] Mozilla Foundation Security Advisory 2026-30: CVE-2026-6771
Mozilla Foundation Security Advisory 2026-30
CVE: CVE-2026-6771
Product: Firefox
Impact: high
Fixed in: Firefox 150
Mozilla
Mozilla Foundation Security Advisory 2026-33: CVE-2026-6771
vendor_mozilla·CVSS 9.8
CVE-2026-6771 [CRITICAL] Mozilla Foundation Security Advisory 2026-33: CVE-2026-6771
Mozilla Foundation Security Advisory 2026-33
CVE: CVE-2026-6771
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 150
GHSA
GHSA-88fc-5m2g-g6q2: Mitigation bypass in the DOM: Security component
ghsa_unreviewed·2026-04-21
CVE-2026-6771 [CRITICAL] CWE-288 GHSA-88fc-5m2g-g6q2: Mitigation bypass in the DOM: Security component
Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 150 and Firefox ESR 140.10.
No detection rules found.
No public exploits indexed.
2026-04-21
Published