CVE-2026-4721

Memory safety bugs present in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2013762%2C2015291%2C2016591%2C2016661%2C2016664%2C2017303%2C2017894%2C2018090%2C2018196%2C2018379%2C2019112%2C2022090%2C2022243%2C2022351%2C2022478%2C2022676	Broken Link
https://www.mozilla.org/security/advisories/mfsa2026-20/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-21/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-22/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-23/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-24/	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:mozilla:firefox:::::esr:::*
	cpe:2.3:a:mozilla:firefox:::::-:::*
	cpe:2.3:a:mozilla:firefox:::::esr:::*
	cpe:2.3:a:mozilla:thunderbird:::::esr:::*
	cpe:2.3:a:mozilla:thunderbird:::::-:::*

History

No history.

Information

Published : 2026-03-24 13:16

Updated : 2026-03-25 20:04

NVD link : CVE-2026-4721

Mitre link : CVE-2026-4721

CVE.ORG link : CVE-2026-4721

JSON object : View

Products Affected

mozilla

firefox
thunderbird

CWE

CWE-120

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

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