CVE-2026-92021

HIGH 8.8CVE-2026-92021 · Published 15/09/2026 · updated 06/10/2026

In short

CVE-2026-92021 is a HIGH (CVSS 8.8) vulnerability affecting firefox (mozilla), thunderbird (mozilla).
Chance of exploitation in the next 30 days (EPSS): 0.28%, higher than 20.8% of all vulnerabilities.
Fix: update to 140.16.0 or later.

Package	Affected versions	Patched versions
firefox mozilla	`< 140.16.0`	`140.16.0`
thunderbird mozilla	`< 140.16.0`	`140.16.0`

Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox ESR 140.16 and Thunderbird 140.16.

Running one of these products? Scan your site to see whether it exposes a vulnerable version.

Package

Affected versions

Patched versions

< 140.16.0

140.16.0

< 140.16.0

140.16.0

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