CVE-2026-8949: Integer overflow in the Widget: Win32 component
Published May 19, 2026
·Updated
Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Affected Software
8 affected componentsFixes available
Mozilla Firefox<151
151
Mozilla Firefox ESR<140.11
140.11
Mozilla Thunderbird<151
151
Mozilla Thunderbird<140.11
140.11
Mozilla Firefox<140.11.0
Mozilla Firefox<151.0.0
Mozilla Thunderbird<140.11
Mozilla Thunderbird<151.0.0
Event History
May 19, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
Updated
via Mozilla·12:00 AM
Affected Software
CVE Published
via MITRE·12:29 PM
Data Sourced
via MITRE·12:29 PM
Description
Data Sourced
via NVD·02:16 PM
DescriptionSeverityWeaknessAffected Software
Jan 18, 58356
Event
via FIRST·03:25 AM
Frequently Asked Questions
1
What is the severity of CVE-2026-8949?
The severity of CVE-2026-8949 is rated high with a CVSS score of 7.5.
2
How do I fix CVE-2026-8949?
To fix CVE-2026-8949, update to Firefox 151, Firefox ESR 140.11, Thunderbird 151, or Thunderbird 140.11.
3
What products are affected by CVE-2026-8949?
CVE-2026-8949 affects Mozilla Thunderbird, Mozilla Firefox, and Mozilla Firefox ESR.
4
What type of vulnerability is CVE-2026-8949?
CVE-2026-8949 is classified as an integer overflow vulnerability.
5
When was CVE-2026-8949 published?
CVE-2026-8949 was published on May 19, 2026.