CVE-2026-6786 Details
Description
Memory safety bugs present in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149. 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 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
A vulnerability has been identified in Mozilla Firefox and Thunderbird, specifically in versions 149 and 140.9, respectively. This vulnerability arises from memory safety issues that could potentially be exploited to execute arbitrary code. Some of these memory safety bugs showed signs of memory corruption, indicating a possibility of exploitation.
Users can upgrade to Firefox 150, Firefox ESR 140.10, Thunderbird 150, or Thunderbird ESR 140.10 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 Apr 22, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-125 | Out-of-bounds Read | CISA-ADP |
| CWE-416 | Use After Free | CISA-ADP |
| CWE-787 | Out-of-bounds Write | redhat-SADP |
| CWE-787 | Out-of-bounds Write | CISA-ADP |
Affected Products
| Product | Versions |
|---|---|
| mozilla firefox | < 150.0 >= 140.0, < 140.10.0 |
CPE
Remediation
| |
| mozilla thunderbird | >= 140.0, < 140.10.0 |
CPE
Remediation
| |
Change History
8 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 15, 2026 | CVE Modified | redhat-SADP |
| Jun 30, 2026 | CVE Modified | redhat-SADP |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 17, 2026 | CVE Modified | [email protected] |
| May 26, 2026 | CVE Modified | CISA-ADP |
| Apr 28, 2026 | Initial Analysis | [email protected] |
| Apr 26, 2026 | CVE Modified | CISA-ADP |
| Apr 26, 2026 | New CVE Received | [email protected] |