CVE-2026-5735

Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. 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 was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

V3 Legend

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=2025475%2C2025477	Broken Link Issue Tracking
https://www.mozilla.org/security/advisories/mfsa2026-25/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-28/

Configurations

Configuration 1 (hide)

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

History

10 May 2026, 21:16

Type	Values Removed	Values Added
CWE		CWE-125

13 Apr 2026, 15:17

Type	Values Removed	Values Added
Summary	(en) Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. 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 < 149.0.2 and Thunderbird < 149.0.2.	(en) Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. 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 was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.

07 Apr 2026, 19:16

Type	Values Removed	Values Added
Summary	(en) Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. 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 < 149.0.2.	(en) Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. 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 < 149.0.2 and Thunderbird < 149.0.2.
References		() https://www.mozilla.org/security/advisories/mfsa2026-28/ -

07 Apr 2026, 18:07

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 9.8
References	~~() https://bugzilla.mozilla.org/buglist.cgi?bug_id=2025475%2C2025477 -~~	() https://bugzilla.mozilla.org/buglist.cgi?bug_id=2025475%2C2025477 - Broken Link, Issue Tracking
References	~~() https://www.mozilla.org/security/advisories/mfsa2026-25/ -~~	() https://www.mozilla.org/security/advisories/mfsa2026-25/ - Vendor Advisory
CWE		CWE-787
CPE		cpe:2.3:a:mozilla:firefox:::::-:::* cpe:2.3:a:mozilla:thunderbird:::::-:::*
First Time		Mozilla Mozilla firefox Mozilla thunderbird

07 Apr 2026, 13:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-04-07 13:16

Updated : 2026-05-10 21:16

NVD link : CVE-2026-5735

Mitre link : CVE-2026-5735

CVE.ORG link : CVE-2026-5735

JSON object : View

Products Affected

mozilla

firefox
thunderbird

CWE

CWE-787

Out-of-bounds Write

CWE-125

Out-of-bounds Read

9.8 /10