CVE-2026-100780
published 2026-09-29CVE-2026-100780: Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4…
PriorityP346high8.8CVSS 3.1
AVNACLPRNUIRSUCHIHAH
EPSS
0.32%
23.3th percentile
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
Affected
18 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 157 | Firefox 157 |
| mozilla | firefox | < 157.0.0 | 157.0.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 115.1.0 < 115.42.0 | 115.42.0 |
| mozilla | firefox | >= 140.0 < 140.17.0 | 140.17.0 |
| mozilla | firefox | >= 153.0 < 153.4.0 | 153.4.0 |
| mozilla | firefox_esr | < Firefox ESR 115.42 | Firefox ESR 115.42 |
| mozilla | firefox_esr | < Firefox ESR 153.4 | Firefox ESR 153.4 |
| mozilla | firefox_esr | < Firefox ESR 140.17 | Firefox ESR 140.17 |
| mozilla | thunderbird | < Thunderbird 157 | Thunderbird 157 |
| mozilla | thunderbird | < Thunderbird 153.4 | Thunderbird 153.4 |
| mozilla | thunderbird | < Thunderbird 140.17 | Thunderbird 140.17 |
| mozilla | thunderbird | < 157.0 | 157.0 |
| mozilla | thunderbird | — | — |
| mozilla | thunderbird | >= 140.0 < 140.17.0 | 140.17.0 |
| mozilla | thunderbird | >= 153.0 < 153.4.0 | 153.4.0 |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
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
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Red Hat
firefox: thunderbird: Use-after-free in the DOM: Core & HTML component
vendor_redhat·2026-09-29·CVSS 8.8
CVE-2026-100780 [HIGH] CWE-416 firefox: thunderbird: Use-after-free in the DOM: Core & HTML component
firefox: thunderbird: Use-after-free in the DOM: Core & HTML component
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Use-after-free in the DOM: Core & HTML component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Mitigation: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread in
Mozilla
Mozilla Foundation Security Advisory 2026-101: CVE-2026-100780
vendor_mozilla·CVSS 8.8
CVE-2026-100780 [HIGH] Mozilla Foundation Security Advisory 2026-101: CVE-2026-100780
Mozilla Foundation Security Advisory 2026-101
CVE: CVE-2026-100780
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 157
Mozilla
Mozilla Foundation Security Advisory 2026-103: CVE-2026-100780
vendor_mozilla·CVSS 8.8
CVE-2026-100780 [HIGH] Mozilla Foundation Security Advisory 2026-103: CVE-2026-100780
Mozilla Foundation Security Advisory 2026-103
CVE: CVE-2026-100780
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 153.4
Mozilla
Mozilla Foundation Security Advisory 2026-102: CVE-2026-100780
vendor_mozilla·CVSS 8.8
CVE-2026-100780 [HIGH] Mozilla Foundation Security Advisory 2026-102: CVE-2026-100780
Mozilla Foundation Security Advisory 2026-102
CVE: CVE-2026-100780
Product: Thunderbird
Impact: moderate
Fixed in: Thunderbird 140.17
Mozilla
Mozilla Foundation Security Advisory 2026-98: CVE-2026-100780
vendor_mozilla·CVSS 8.8
CVE-2026-100780 [HIGH] Mozilla Foundation Security Advisory 2026-98: CVE-2026-100780
Mozilla Foundation Security Advisory 2026-98
CVE: CVE-2026-100780
Product: Firefox ESR
Impact: moderate
Fixed in: Firefox ESR 115.42
Mozilla
Mozilla Foundation Security Advisory 2026-100: CVE-2026-100780
vendor_mozilla·CVSS 8.8
CVE-2026-100780 [HIGH] Mozilla Foundation Security Advisory 2026-100: CVE-2026-100780
Mozilla Foundation Security Advisory 2026-100
CVE: CVE-2026-100780
Product: Firefox ESR
Impact: low
Fixed in: Firefox ESR 153.4
Mozilla
Mozilla Foundation Security Advisory 2026-97: CVE-2026-100780
vendor_mozilla·CVSS 8.8
CVE-2026-100780 [HIGH] Mozilla Foundation Security Advisory 2026-97: CVE-2026-100780
Mozilla Foundation Security Advisory 2026-97
CVE: CVE-2026-100780
Product: Firefox
Impact: low
Fixed in: Firefox 157
Mozilla
Mozilla Foundation Security Advisory 2026-99: CVE-2026-100780
vendor_mozilla·CVSS 8.8
CVE-2026-100780 [HIGH] Mozilla Foundation Security Advisory 2026-99: CVE-2026-100780
Mozilla Foundation Security Advisory 2026-99
CVE: CVE-2026-100780
Product: Firefox ESR
Impact: moderate
Fixed in: Firefox ESR 140.17
VulDB
Mozilla Firefox up to 115.41/140.16/153.3/156 DOM Core/HTML use after free (WID-SEC-2026-3654)
vuldb·2026-10-03·CVSS 8.8
CVE-2026-100780 [HIGH] Mozilla Firefox up to 115.41/140.16/153.3/156 DOM Core/HTML use after free (WID-SEC-2026-3654)
A vulnerability, which was classified as critical, was found in Mozilla Firefox up to 115.41/140.16/153.3/156. Impacted is an unknown function of the component DOM Core/HTML. Such manipulation leads to use after free.
This vulnerability is referenced as CVE-2026-100780. It is possible to launch the attack remotely. No exploit is available.
You should upgrade the affected component.
GHSA
Use-after-free in the DOM: Core & HTML component.
ghsa_unreviewed·2026-09-29
CVE-2026-100780 [HIGH] CWE-416 Use-after-free in the DOM: Core & HTML component.
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
No detection rules found.
No public exploits indexed.
https://bugzilla.mozilla.org/show_bug.cgi?id=2068422https://www.mozilla.org/security/advisories/mfsa2026-100/https://www.mozilla.org/security/advisories/mfsa2026-101/https://www.mozilla.org/security/advisories/mfsa2026-102/https://www.mozilla.org/security/advisories/mfsa2026-103/https://www.mozilla.org/security/advisories/mfsa2026-97/https://www.mozilla.org/security/advisories/mfsa2026-98/https://www.mozilla.org/security/advisories/mfsa2026-99/
2026-09-29
Published