CVE-2026-8949 Details
Description
Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
An integer overflow vulnerability has been identified in the Widget: Win32 component of Mozilla Firefox. This issue affects Firefox versions prior to 151 and Firefox ESR versions prior to 140.11. The vulnerability arises from improper handling of integer values, which can lead to unexpected behavior or conditions.
Users can upgrade to Firefox 151 or Firefox ESR 140.11 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 19, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://bugzilla.mozilla.org/show_bug.cgi?id=1355639 | [email protected] | Permissions Required |
| https://www.mozilla.org/security/advisories/mfsa2026-46/ | [email protected] | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2026-48/ | [email protected] | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2026-50/ | [email protected] | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2026-51/ | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-190 | Integer Overflow or Wraparound | CISA-ADP |
Affected Products
| Product | Versions |
|---|---|
| mozilla firefox | < 140.11.0 < 151.0.0 |
CPE
Remediation
| |
| mozilla thunderbird | < 140.11 < 151.0.0 |
CPE
Remediation
| |
Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 20, 2026 | Initial Analysis | [email protected] |
| May 19, 2026 | CVE Modified | [email protected] |
| May 19, 2026 | CVE Modified | CISA-ADP |
| May 19, 2026 | New CVE Received | [email protected] |