CVE-2026-12306: Vulnerability in Mozilla Firefox
Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
AI Analysis
Technical Summary
CVE-2026-12306 is a memory safety bug in Mozilla Firefox identified and fixed in Firefox 152 and Firefox ESR 140.12. It is part of a broader set of memory safety vulnerabilities addressed simultaneously, some of which showed evidence of memory corruption that could lead to arbitrary code execution. Mozilla released official security advisories MFSA2026-57 and MFSA2026-58 detailing these fixes. The vulnerability affects Firefox and Firefox ESR versions prior to 152 and 140.12 respectively. No CVSS score is provided, but the impact is assessed as moderate by Mozilla. There are no known exploits in the wild for this specific CVE.
Potential Impact
The vulnerability is a memory safety bug that could lead to memory corruption. Such corruption may be leveraged by attackers to execute arbitrary code within the context of the affected Firefox process. This poses a risk to user security and system integrity. However, no active exploitation has been reported. The impact is considered moderate by Mozilla.
Mitigation Recommendations
Mozilla has released official fixes for this vulnerability in Firefox 152 and Firefox ESR 140.12. Users and administrators should update affected Firefox installations to these versions or later to remediate the vulnerability. Since this is not a cloud service, patching the client software is required. No additional mitigation steps are indicated by the vendor advisories.
CVE-2026-12306: Vulnerability in Mozilla Firefox
Description
Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
CVSS v3.1
Score 5.3medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-12306 is a memory safety bug in Mozilla Firefox identified and fixed in Firefox 152 and Firefox ESR 140.12. It is part of a broader set of memory safety vulnerabilities addressed simultaneously, some of which showed evidence of memory corruption that could lead to arbitrary code execution. Mozilla released official security advisories MFSA2026-57 and MFSA2026-58 detailing these fixes. The vulnerability affects Firefox and Firefox ESR versions prior to 152 and 140.12 respectively. No CVSS score is provided, but the impact is assessed as moderate by Mozilla. There are no known exploits in the wild for this specific CVE.
Potential Impact
The vulnerability is a memory safety bug that could lead to memory corruption. Such corruption may be leveraged by attackers to execute arbitrary code within the context of the affected Firefox process. This poses a risk to user security and system integrity. However, no active exploitation has been reported. The impact is considered moderate by Mozilla.
Mitigation Recommendations
Mozilla has released official fixes for this vulnerability in Firefox 152 and Firefox ESR 140.12. Users and administrators should update affected Firefox installations to these versions or later to remediate the vulnerability. Since this is not a cloud service, patching the 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
- 2026-06-15T15:08:13.015Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-57/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-58/","vendor":"Mozilla"}]
Threat ID: 6a314c7e0b89be6888b4cc99
Added to database: 6/16/2026, 1:15:42 PM
Last enriched: 6/16/2026, 1:45:55 PM
Last updated: 6/17/2026, 4:24:22 AM
Views: 3
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