CVE-2026-5734: Vulnerability in Mozilla Firefox
Memory safety bugs present in Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. 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 149.0.2, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.
AI Analysis
Technical Summary
This vulnerability consists of memory safety bugs in specific versions of Mozilla Firefox and Thunderbird, including ESR 140.9.0 and 149.0.1 releases. The bugs showed evidence of memory corruption, which could be leveraged to execute arbitrary code. Mozilla has addressed these issues by releasing patched versions: Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2, and Thunderbird 149.0.2. The CVSS score is 8.1, indicating high severity, with attack vector network, high complexity, no privileges required, no user interaction, and high impact on confidentiality, integrity, and availability. The vendor advisories mfsa2026-25 and mfsa2026-27 provide detailed information and confirm the fixes.
Potential Impact
Successful exploitation of these memory safety bugs could allow an attacker to execute arbitrary code remotely without user interaction or privileges, potentially compromising confidentiality, integrity, and availability of the affected systems. However, no known exploits are currently reported in the wild.
Mitigation Recommendations
Mozilla has released official patches fixing these vulnerabilities in Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2, and Thunderbird 149.0.2. Users and administrators should update to these versions immediately to mitigate the risk. Since patches are available and the vendor advisory confirms the fix, applying these updates is the recommended remediation.
CVE-2026-5734: Vulnerability in Mozilla Firefox
Description
Memory safety bugs present in Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. 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 149.0.2, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability consists of memory safety bugs in specific versions of Mozilla Firefox and Thunderbird, including ESR 140.9.0 and 149.0.1 releases. The bugs showed evidence of memory corruption, which could be leveraged to execute arbitrary code. Mozilla has addressed these issues by releasing patched versions: Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2, and Thunderbird 149.0.2. The CVSS score is 8.1, indicating high severity, with attack vector network, high complexity, no privileges required, no user interaction, and high impact on confidentiality, integrity, and availability. The vendor advisories mfsa2026-25 and mfsa2026-27 provide detailed information and confirm the fixes.
Potential Impact
Successful exploitation of these memory safety bugs could allow an attacker to execute arbitrary code remotely without user interaction or privileges, potentially compromising confidentiality, integrity, and availability of the affected systems. However, no known exploits are currently reported in the wild.
Mitigation Recommendations
Mozilla has released official patches fixing these vulnerabilities in Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2, and Thunderbird 149.0.2. Users and administrators should update to these versions immediately to mitigate the risk. Since patches are available and the vendor advisory confirms the fix, applying these updates is the recommended remediation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-04-07T12:43:14.328Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-25/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-27/","vendor":"Mozilla"}]
Threat ID: 69d50016aaed68159a219ce2
Added to database: 4/7/2026, 1:01:10 PM
Last enriched: 5/15/2026, 9:24:29 AM
Last updated: 5/22/2026, 11:28:18 AM
Views: 149
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