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Vulnerability IntelligenceCVE-2026-0884

CVE-2026-0884

CRITICAL9.8

Use-after-free in the JavaScript Engine component

Published Jan 13, 2026

Modified 5 days ago

Fix available

Details

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

Affected Packages

Firefox

Ubuntu 14.04 LTSUbuntu 16.04 LTSUbuntu 18.04 LTSUbuntu 20.04 LTSUbuntu 22.04 LTS

Fixed in:

147

Mozilla Firefox

Windows 10 (1507)Windows 10 (1607) / Server 2016Windows 10 (1809) / Server 2019Windows 10 (1903)Windows 10 (1909)

Fixed in:

147

Mozilla Firefox ESR

Windows 10 (1507)Windows 10 (1607) / Server 2016Windows 10 (1809) / Server 2019Windows 10 (1903)Windows 10 (1909)

Fixed in:

140.7

Firefox ESR

macOS 14macOS 15macOS 26

Fixed in:

140.7

References

WEBhttps://bugzilla.mozilla.org/show_bug.cgi?id=2003588 ADVISORYhttps://www.cve.org/CVERecord?id=CVE-2026-0884 WEBhttps://www.mozilla.org/security/advisories/mfsa2026-01/WEBhttps://www.mozilla.org/security/advisories/mfsa2026-03/WEBhttps://www.mozilla.org/security/advisories/mfsa2026-04/WEBhttps://www.mozilla.org/security/advisories/mfsa2026-05/

CVSS Analysis

CVSS v3.1

9.8

Exploitability

Attack Vector

NetworkAV:N

Attack Complexity

LowAC:L

Privileges Required

NonePR:N

User Interaction

NoneUI:N

Scope

UnchangedS:U

Impact

Confidentiality

HighC:H

Integrity

HighI:H

Availability

HighA:H

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

Ecosystems(28)

Ubuntu 14.04 LTS Ubuntu 16.04 LTS Ubuntu 18.04 LTS Ubuntu 20.04 LTS Ubuntu 22.04 LTS

Timeline

PublishedJan 13, 2026

ModifiedJan 15, 2026

CVE-2026-0884 | Mondoo Vulnerability Intelligence