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 and Firefox ESR 140.10.
AI Analysis
Technical Summary
This vulnerability involves multiple memory safety bugs in Mozilla Firefox and Thunderbird versions prior to Firefox 150 and ESR 140.10. These bugs include use-after-free, uninitialized memory, incorrect boundary conditions, and other memory corruption issues that could allow an attacker to execute arbitrary code with sufficient effort. The issues were identified and fixed by the Mozilla Fuzzing Team and other contributors. The vendor advisories (MFSA 2026-30 and MFSA 2026-32) provide detailed information on the affected components and confirm that the vulnerabilities have been remediated in the specified fixed versions.
Potential Impact
The vulnerabilities could lead to arbitrary code execution due to memory corruption, which is considered a high impact. Exploitation could allow attackers to run malicious code within the context of the affected applications. However, there are no reports of active exploitation in the wild. The impact affects users running the specified vulnerable versions of Firefox and Thunderbird.
Mitigation Recommendations
Official fixes are available and have been released in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird ESR 140.10. Users and administrators should update to these fixed versions to remediate the vulnerabilities. No additional mitigation actions are required beyond applying these official updates.
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 and Firefox ESR 140.10.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves multiple memory safety bugs in Mozilla Firefox and Thunderbird versions prior to Firefox 150 and ESR 140.10. These bugs include use-after-free, uninitialized memory, incorrect boundary conditions, and other memory corruption issues that could allow an attacker to execute arbitrary code with sufficient effort. The issues were identified and fixed by the Mozilla Fuzzing Team and other contributors. The vendor advisories (MFSA 2026-30 and MFSA 2026-32) provide detailed information on the affected components and confirm that the vulnerabilities have been remediated in the specified fixed versions.
Potential Impact
The vulnerabilities could lead to arbitrary code execution due to memory corruption, which is considered a high impact. Exploitation could allow attackers to run malicious code within the context of the affected applications. However, there are no reports of active exploitation in the wild. The impact affects users running the specified vulnerable versions of Firefox and Thunderbird.
Mitigation Recommendations
Official fixes are available and have been released in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird ESR 140.10. Users and administrators should update to these fixed versions to remediate the vulnerabilities. No additional mitigation actions are required beyond applying these official updates.
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: 4/21/2026, 1:16:20 PM
Last enriched: 4/21/2026, 1:31:13 PM
Last updated: 4/21/2026, 2:30:02 PM
Views: 4
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