CVE-2026-4716

CRITICAL

Incorrect boundary conditions, uninitialized memory in the JavaScript Engine component

Title source: cna

Description

Incorrect boundary conditions, uninitialized memory in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

References (5)

https://bugzilla.mozilla.org/show_bug.cgi?id=2018592

https://www.mozilla.org/security/advisories/mfsa2026-20/

https://www.mozilla.org/security/advisories/mfsa2026-22/

https://www.mozilla.org/security/advisories/mfsa2026-23/

https://www.mozilla.org/security/advisories/mfsa2026-24/

Scores

CVSS v3 9.1

EPSS 0.0003

EPSS Percentile 6.8%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

CWE

CWE-908

Status published

Products (10)

mozilla/firefox < 140.9.0

mozilla/firefox < 149.0

Mozilla/Firefox 140.9 - 140.*

Mozilla/Firefox 149

Mozilla/Firefox unspecified - 149

Mozilla/Firefox ESR unspecified - 140.9

Mozilla/Thunderbird 140.9 - 140.*

Mozilla/Thunderbird 149

Mozilla/Thunderbird unspecified - 140.9

Mozilla/Thunderbird unspecified - 149

Published Mar 24, 2026

Tracked Since Mar 24, 2026