CVE-2026-6786: Vulnerability in Mozilla Firefox
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.
AI Analysis
Technical Summary
This vulnerability involves multiple memory safety bugs in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149, and Thunderbird 149. The bugs include use-after-free, uninitialized memory, and incorrect boundary conditions, which can lead to memory corruption. Mozilla has addressed these issues in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird ESR 140.10. The CVSS score is 7.5 (high severity) with network attack vector, high complexity, no privileges required, user interaction required, and high impact on confidentiality, integrity, and availability. The vendor advisories (MFSA 2026-30 and MFSA 2026-32) confirm the fixes and provide detailed references to the individual bugs.
Potential Impact
Successful exploitation of these memory safety bugs could allow an attacker to execute arbitrary code remotely, potentially compromising confidentiality, integrity, and availability of the affected systems. The vulnerabilities are rated high severity with a CVSS score of 7.5. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
Official fixes are available and have been released by Mozilla. Users and administrators should upgrade to Firefox 150, Firefox ESR 140.10, Thunderbird 150, or Thunderbird ESR 140.10 to remediate these vulnerabilities. Since this is not a cloud service, patching the affected client software is required. No additional mitigation steps are indicated by the vendor advisories.
CVE-2026-6786: Vulnerability in Mozilla Firefox
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.
CVSS v3.1
Score 7.5high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves multiple memory safety bugs in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149, and Thunderbird 149. The bugs include use-after-free, uninitialized memory, and incorrect boundary conditions, which can lead to memory corruption. Mozilla has addressed these issues in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird ESR 140.10. The CVSS score is 7.5 (high severity) with network attack vector, high complexity, no privileges required, user interaction required, and high impact on confidentiality, integrity, and availability. The vendor advisories (MFSA 2026-30 and MFSA 2026-32) confirm the fixes and provide detailed references to the individual bugs.
Potential Impact
Successful exploitation of these memory safety bugs could allow an attacker to execute arbitrary code remotely, potentially compromising confidentiality, integrity, and availability of the affected systems. The vulnerabilities are rated high severity with a CVSS score of 7.5. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
Official fixes are available and have been released by Mozilla. Users and administrators should upgrade to Firefox 150, Firefox ESR 140.10, Thunderbird 150, or Thunderbird ESR 140.10 to remediate these vulnerabilities. Since this is not a cloud service, patching the affected client software is required. No additional mitigation steps are indicated by the vendor advisories.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-04-21T12:41:14.326Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-30/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-32/","vendor":"Mozilla"}]
Threat ID: 69e778a419fe3cd2cdd1666b
Added to database: 04/21/2026, 13:16:20 UTC
Last enriched: 07/15/2026, 09:37:43 UTC
Last updated: 07/31/2026, 19:23:00 UTC
Views: 251
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