CVE-2026-4698

CriticalCVSS 9.8

Published: 24/03/2026(UTC)Updated: 15/07/2026(UTC)Translated: 16/07/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Elevated risk

0.76%

51th percentile - higher than 51% of all known CVEs

Summary

A JIT miscompilation vulnerability was found in the JavaScript Engine of Firefox and Thunderbird. It was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Risk Assessment

An attacker could exploit this vulnerability to execute arbitrary code in the context of the browser or mail client, potentially leading to system compromise or data theft.

Recommendation

Immediately update Firefox and Thunderbird to the versions specified in the advisory (Firefox 149, Firefox ESR 115.34/140.9, Thunderbird 149/140.9).

Original NVD description (English source)

JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.