CVE Vulnerabilities

CVE-2026-12299

Access of Resource Using Incompatible Type ('Type Confusion')

Published: Jun 16, 2026 | Modified: Jun 17, 2026
CVSS 3.x
N/A
Source:
NVD
CVSS 2.x
RedHat/V2
RedHat/V3
7.5 IMPORTANT
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Ubuntu
MEDIUM
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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.

Weakness

The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

Affected Software

NameVendorStart VersionEnd Version
FirefoxMozilla*115.37.0 (excluding)
FirefoxMozilla*152.0 (excluding)
FirefoxMozilla140.0 (including)140.12.0 (excluding)
ThunderbirdMozilla*152.0.0 (excluding)
ThunderbirdMozilla140.0 (including)140.12.0 (excluding)
Red Hat Enterprise Linux 10RedHatfirefox-0:140.12.0-1.el10_2*
Red Hat Enterprise Linux 8RedHatfirefox-0:140.12.0-1.el8_10*
Red Hat Enterprise Linux 9RedHatfirefox-0:140.12.0-1.el9_8*
Mozjs102Ubuntuesm-apps/noble*
Mozjs102Ubuntujammy*
Mozjs102Ubuntunoble*
Mozjs115Ubuntunoble*
Mozjs52Ubuntuesm-apps/focal*
Mozjs52Ubuntuesm-infra/bionic*
Mozjs68Ubuntuesm-infra/focal*
Mozjs78Ubuntuesm-apps/jammy*
Mozjs78Ubuntujammy*
Mozjs91Ubuntujammy*
ThunderbirdUbuntujammy*

Extended Description

When the product accesses the resource using an incompatible type, this could trigger logical errors because the resource does not have expected properties. In languages without memory safety, such as C and C++, type confusion can lead to out-of-bounds memory access. While this weakness is frequently associated with unions when parsing data with many different embedded object types in C, it can be present in any application that can interpret the same variable or memory location in multiple ways. This weakness is not unique to C and C++. For example, errors in PHP applications can be triggered by providing array parameters when scalars are expected, or vice versa. Languages such as Perl, which perform automatic conversion of a variable of one type when it is accessed as if it were another type, can also contain these issues.

References