CVE-2026-0884

CRITICAL

Firefox < 147.0 and < 140.7.0 - Use-After-Free in JavaScript Engine

Title source: llm

Description

Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

References (5)

Core 5

Core References

Permissions Required

https://bugzilla.mozilla.org/show_bug.cgi?id=2003588

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2026-01/

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2026-03/

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2026-04/

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2026-05/

Scores

CVSS v3 9.8

EPSS 0.0003

EPSS Percentile 9.0%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact total

Details

CWE

CWE-416

Status published

Products (8)

mozilla/firefox < 140.7.0

mozilla/firefox < 147.0

Mozilla/Firefox 140.7 - 140.*

Mozilla/Firefox 147

mozilla/thunderbird < 140.7.0

mozilla/thunderbird < 147.0

Mozilla/Thunderbird 140.7 - 140.*

Mozilla/Thunderbird 147

Published Jan 13, 2026

Tracked Since Feb 18, 2026