Memory safety bugs present in 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 and Thunderbird < 149.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable yes

Technical Impact total

Affected Vendors & Products

Vendors Products
Mozilla
  • Firefox
  • Thunderbird

Configuration 1 [-]

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

No data.

References
Link Providers
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1944033%2C1997282%2C2009213%2C2011412%2C2021925%2C2022034 cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-4729 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-4729 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-20/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-20/#CVE-2026-4729 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-23/ cve-icon cve-icon
History

Wed, 25 Mar 2026 21:00:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
Vendors & Products Mozilla thunderbird

Wed, 25 Mar 2026 13:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-120
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}

 ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Wed, 25 Mar 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-825
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}

threat_severity

Important

Wed, 25 Mar 2026 12:00:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox

Tue, 24 Mar 2026 20:30:00 +0000

Type Values Removed Values Added
Description Memory safety bugs present in 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. Memory safety bugs present in 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 and Thunderbird < 149.
References

Tue, 24 Mar 2026 12:45:00 +0000

Type Values Removed Values Added
Description Memory safety bugs present in 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.
Title Memory safety bugs fixed in Firefox 149 and Thunderbird 149
References
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-03-25T13:08:59.287Z

Reserved: 2026-03-23T23:22:57.190Z

Link: CVE-2026-4729

cve-icon Vulnrichment

Updated: 2026-03-25T13:08:55.754Z

cve-icon NVD

Status : Analyzed

Published: 2026-03-24T13:16:08.830

Modified: 2026-03-25T20:54:55.353

Link: CVE-2026-4729

cve-icon Redhat

Severity : Important

Publid Date: 2026-03-24T12:30:43Z

Links: CVE-2026-4729 - Bugzilla