CVE-2026-84129
published 2026-09-01CVE-2026-84129: Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
PriorityP353critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
0.18%
8.2th percentile
Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
Affected
8 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 155 | Firefox 155 |
| mozilla | firefox | < 153.2.0 | 153.2.0 |
| mozilla | firefox | >= 154.0.0 < 155.0.0 | 155.0.0 |
| mozilla | firefox_esr | < Firefox ESR 153.2 | Firefox ESR 153.2 |
| mozilla | thunderbird | < Thunderbird 153.2 | Thunderbird 153.2 |
| mozilla | thunderbird | < Thunderbird 155 | Thunderbird 155 |
| mozilla | thunderbird | < 153.2.0 | 153.2.0 |
| mozilla | thunderbird | >= 154.0 < 155.0 | 155.0 |
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Mozilla
Mozilla Foundation Security Advisory 2026-88: CVE-2026-84129
vendor_mozilla
CVE-2026-84129 Mozilla Foundation Security Advisory 2026-88: CVE-2026-84129
Mozilla Foundation Security Advisory 2026-88
CVE: CVE-2026-84129
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 153.2
Mozilla
Mozilla Foundation Security Advisory 2026-82: CVE-2026-84129
vendor_mozilla
CVE-2026-84129 Mozilla Foundation Security Advisory 2026-82: CVE-2026-84129
Mozilla Foundation Security Advisory 2026-82
CVE: CVE-2026-84129
Product: Firefox
Impact: high
Fixed in: Firefox 155
Mozilla
Mozilla Foundation Security Advisory 2026-86: CVE-2026-84129
vendor_mozilla
CVE-2026-84129 Mozilla Foundation Security Advisory 2026-86: CVE-2026-84129
Mozilla Foundation Security Advisory 2026-86
CVE: CVE-2026-84129
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 155
Mozilla
Mozilla Foundation Security Advisory 2026-85: CVE-2026-84129
vendor_mozilla
CVE-2026-84129 Mozilla Foundation Security Advisory 2026-85: CVE-2026-84129
Mozilla Foundation Security Advisory 2026-85
CVE: CVE-2026-84129
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 153.2
VulDB
Mozilla Firefox up to 153.1/154 Navigation isolation (Nessus ID 342312)
vuldb·2026-09-03·CVSS 9.8
CVE-2026-84129 [CRITICAL] Mozilla Firefox up to 153.1/154 Navigation isolation (Nessus ID 342312)
A vulnerability was found in Mozilla Firefox up to 153.1/154. It has been rated as critical. Affected by this issue is some unknown functionality of the component Navigation Component. The manipulation leads to improper isolation or compartmentalization.
This vulnerability is uniquely identified as CVE-2026-84129. The attack is possible to be carried out remotely. No exploit exists.
Upgrading the affected component is advised.
GHSA
Site isolation issue in the DOM: Navigation component.
ghsa_unreviewed·2026-09-01
CVE-2026-84129 Site isolation issue in the DOM: Navigation component.
Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155 and Firefox ESR 153.2.
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-09-01
Published