CVE-2026-4723 Use-after-free in the JavaScript Engine component

Description

Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149 and Thunderbird 149.

Affected products and versions

Product	Affected versions	Fixed in
Firefox 149	earliest → < 149	149
Thunderbird 149	earliest → < 149	149

Other CVEs of Firefox

The 2221 CVEs of Firefox →

CVE-2026-120572 Incorrect boundary conditions in the Layout: Block and Inline component 8.8 High CVE-2026-118027 Frame poisoning in the Layout component 9.1 Critical CVE-2026-118026 Invalid pointer in the JavaScript: GC component 8.8 High CVE-2026-118025 Other issue in the SVG component 8.8 High