CVE-2026-12299
published 2026-06-16CVE-2026-12299: JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and…
PriorityP425medium5.4CVSS 3.1
AVNACLPRNUIRSUCLILAN
EPSS
0.31%
22.4th percentile
JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
Affected
14 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 152 | Firefox 152 |
| mozilla | firefox | < 115.37.0 | 115.37.0 |
| mozilla | firefox | < 152.0 | 152.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 140.0 < 140.12.0 | 140.12.0 |
| mozilla | firefox_esr | < Firefox ESR 140.12 | Firefox ESR 140.12 |
| mozilla | firefox_esr | < Firefox ESR 115.37 | Firefox ESR 115.37 |
| mozilla | thunderbird | < Thunderbird 152 | Thunderbird 152 |
| mozilla | thunderbird | < Thunderbird 140.12 | Thunderbird 140.12 |
| mozilla | thunderbird | < 152.0.0 | 152.0.0 |
| mozilla | thunderbird | — | — |
| mozilla | thunderbird | >= 140.0 < 140.12.0 | 140.12.0 |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
CVSS provenance
nvdv3.15.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
vendor_redhat5.4MEDIUM
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Red Hat
firefox: thunderbird: JIT miscompilation in the DOM: Core & HTML component
vendor_redhat·2026-06-16·CVSS 5.4
CVE-2026-12299 [MEDIUM] CWE-733 firefox: thunderbird: JIT miscompilation in the DOM: Core & HTML component
firefox: thunderbird: JIT miscompilation in the DOM: Core & HTML component
JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
JIT miscompilation 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.
Package: firefox (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: thunderbird (Red Hat E
Mozilla
Mozilla Foundation Security Advisory 2026-60: CVE-2026-12299
vendor_mozilla·CVSS 5.4
CVE-2026-12299 [MEDIUM] Mozilla Foundation Security Advisory 2026-60: CVE-2026-12299
Mozilla Foundation Security Advisory 2026-60
CVE: CVE-2026-12299
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 152
Mozilla
Mozilla Foundation Security Advisory 2026-58: CVE-2026-12299
vendor_mozilla·CVSS 5.4
CVE-2026-12299 [MEDIUM] Mozilla Foundation Security Advisory 2026-58: CVE-2026-12299
Mozilla Foundation Security Advisory 2026-58
CVE: CVE-2026-12299
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.12
Mozilla
Mozilla Foundation Security Advisory 2026-57: CVE-2026-12299
vendor_mozilla·CVSS 5.4
CVE-2026-12299 [MEDIUM] Mozilla Foundation Security Advisory 2026-57: CVE-2026-12299
Mozilla Foundation Security Advisory 2026-57
CVE: CVE-2026-12299
Product: Firefox
Impact: high
Fixed in: Firefox 152
Mozilla
Mozilla Foundation Security Advisory 2026-59: CVE-2026-12299
vendor_mozilla·CVSS 5.4
CVE-2026-12299 [MEDIUM] Mozilla Foundation Security Advisory 2026-59: CVE-2026-12299
Mozilla Foundation Security Advisory 2026-59
CVE: CVE-2026-12299
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.37
Mozilla
Mozilla Foundation Security Advisory 2026-61: CVE-2026-12299
vendor_mozilla·CVSS 5.4
CVE-2026-12299 [MEDIUM] Mozilla Foundation Security Advisory 2026-61: CVE-2026-12299
Mozilla Foundation Security Advisory 2026-61
CVE: CVE-2026-12299
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.12
VulDB
Mozilla Firefox up to 151 HTML type confusion (Nessus ID 321490 / WID-SEC-2026-1959)
vuldb·2026-07-03·CVSS 5.4
CVE-2026-12299 [MEDIUM] Mozilla Firefox up to 151 HTML type confusion (Nessus ID 321490 / WID-SEC-2026-1959)
A vulnerability identified as critical has been detected in Mozilla Firefox up to 151. The affected element is an unknown function of the component HTML Handler. Performing a manipulation results in type confusion.
This vulnerability is cataloged as CVE-2026-12299. It is possible to initiate the attack remotely. There is no exploit available.
You should upgrade the affected component.
GHSA
JIT miscompilation in the DOM: Core & HTML component.
ghsa_unreviewed·2026-06-16
CVE-2026-12299 [MEDIUM] CWE-843 JIT miscompilation in the DOM: Core & HTML component.
JIT miscompilation in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, and Firefox ESR 115.37.
No detection rules found.
No public exploits indexed.
https://bugzilla.mozilla.org/show_bug.cgi?id=2043139https://www.mozilla.org/security/advisories/mfsa2026-57/https://www.mozilla.org/security/advisories/mfsa2026-58/https://www.mozilla.org/security/advisories/mfsa2026-59/https://www.mozilla.org/security/advisories/mfsa2026-60/https://www.mozilla.org/security/advisories/mfsa2026-61/https://access.redhat.com/errata/RHSA-2026:27717https://access.redhat.com/errata/RHSA-2026:27733https://access.redhat.com/errata/RHSA-2026:27734https://access.redhat.com/errata/RHSA-2026:29940https://access.redhat.com/errata/RHSA-2026:30846https://access.redhat.com/errata/RHSA-2026:33445https://access.redhat.com/errata/RHSA-2026:36100https://access.redhat.com/errata/RHSA-2026:36101https://access.redhat.com/errata/RHSA-2026:36102https://access.redhat.com/errata/RHSA-2026:36103https://access.redhat.com/errata/RHSA-2026:37210https://access.redhat.com/errata/RHSA-2026:37391https://access.redhat.com/errata/RHSA-2026:38506https://access.redhat.com/errata/RHSA-2026:38750https://access.redhat.com/errata/RHSA-2026:38751https://access.redhat.com/errata/RHSA-2026:38753https://access.redhat.com/security/cve/CVE-2026-12299https://bugzilla.redhat.com/show_bug.cgi?id=2489212https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12299.json
2026-06-16
Published