CVE-2026-100831
published 2026-09-29CVE-2026-100831: Use-after-free in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and…
PriorityP345high8.8CVSS 3.1
AVNACLPRNUIRSUCHIHAH
EPSS
0.24%
13.7th percentile
Use-after-free in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
Affected
8 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 157 | Firefox 157 |
| mozilla | firefox | < 153.4.0 | 153.4.0 |
| mozilla | firefox | >= 154.0.0 < 157.0.0 | 157.0.0 |
| mozilla | firefox_esr | < Firefox ESR 153.4 | Firefox ESR 153.4 |
| mozilla | thunderbird | < Thunderbird 157 | Thunderbird 157 |
| mozilla | thunderbird | < Thunderbird 153.4 | Thunderbird 153.4 |
| mozilla | thunderbird | < 153.4.0 | 153.4.0 |
| mozilla | thunderbird | >= 154.0 < 157.0 | 157.0 |
CVSS provenance
nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
vendor_redhat8.8HIGH
Stop checking back — get the weekly exploitation signal.
Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.
Red Hat
firefox: Use-after-free in the DOM: UI Events & Focus Handling component
vendor_redhat·2026-09-29·CVSS 8.8
CVE-2026-100831 [HIGH] CWE-825 firefox: Use-after-free in the DOM: UI Events & Focus Handling component
firefox: Use-after-free in the DOM: UI Events & Focus Handling component
Use-after-free in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
Use-after-free in the DOM: UI Events & Focus Handling 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) - Not affected
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Not affected
Package: firefox (Red Hat Enterprise Linux 6) - Not affected
Package: firefox (Red Hat Enterprise Linux 7) - Not affec
Mozilla
Mozilla Foundation Security Advisory 2026-97: CVE-2026-100831
vendor_mozilla·CVSS 8.8
CVE-2026-100831 [HIGH] Mozilla Foundation Security Advisory 2026-97: CVE-2026-100831
Mozilla Foundation Security Advisory 2026-97
CVE: CVE-2026-100831
Product: Firefox
Impact: low
Fixed in: Firefox 157
Mozilla
Mozilla Foundation Security Advisory 2026-101: CVE-2026-100831
vendor_mozilla·CVSS 8.8
CVE-2026-100831 [HIGH] Mozilla Foundation Security Advisory 2026-101: CVE-2026-100831
Mozilla Foundation Security Advisory 2026-101
CVE: CVE-2026-100831
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 157
Mozilla
Mozilla Foundation Security Advisory 2026-100: CVE-2026-100831
vendor_mozilla·CVSS 8.8
CVE-2026-100831 [HIGH] Mozilla Foundation Security Advisory 2026-100: CVE-2026-100831
Mozilla Foundation Security Advisory 2026-100
CVE: CVE-2026-100831
Product: Firefox ESR
Impact: low
Fixed in: Firefox ESR 153.4
Mozilla
Mozilla Foundation Security Advisory 2026-103: CVE-2026-100831
vendor_mozilla·CVSS 8.8
CVE-2026-100831 [HIGH] Mozilla Foundation Security Advisory 2026-103: CVE-2026-100831
Mozilla Foundation Security Advisory 2026-103
CVE: CVE-2026-100831
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 153.4
GHSA
Use-after-free in the DOM: UI Events & Focus Handling component.
ghsa_unreviewed·2026-09-29
CVE-2026-100831 [HIGH] CWE-416 Use-after-free in the DOM: UI Events & Focus Handling component.
Use-after-free in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox ESR 153.4 and Firefox 157.
No detection rules found.
No public exploits indexed.
2026-09-29
Published