Description
Memory safety bugs present in Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146 and Thunderbird 146. 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 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
References (5)
Core 5
Core References
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
8.1
EPSS
0.0003
EPSS Percentile
8.6%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
total
Details
CWE
CWE-119
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