CVE-2026-2766: Vulnerability in Mozilla Firefox
Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
AI Analysis
Technical Summary
CVE-2026-2766 is a use-after-free vulnerability in the Just-In-Time (JIT) compilation component of the JavaScript Engine in Mozilla Firefox. This memory safety flaw could lead to high-impact consequences such as arbitrary code execution. The vulnerability was reported by a team of researchers and fixed in Firefox 148 and Firefox ESR 140.8. The vendor advisory confirms the fix and categorizes the impact as high. The vulnerability is part of a broader set of memory safety issues addressed in the same release cycle.
Potential Impact
Successful exploitation of this use-after-free vulnerability could result in arbitrary code execution with the privileges of the user running Firefox. This can lead to complete compromise of the affected system. The CVSS v3.1 score is 9.8 (critical), reflecting network attack vector, no required privileges or user interaction, and high confidentiality, integrity, and availability impacts.
Mitigation Recommendations
Mozilla has released official fixes for this vulnerability in Firefox 148 and Firefox ESR 140.8. Users and administrators should update affected Firefox installations to these versions or later to remediate the issue. No additional mitigation steps are required beyond applying the official update.
CVE-2026-2766: Vulnerability in Mozilla Firefox
Description
Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
CVSS v3.1
Score 9.8critical
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-2766 is a use-after-free vulnerability in the Just-In-Time (JIT) compilation component of the JavaScript Engine in Mozilla Firefox. This memory safety flaw could lead to high-impact consequences such as arbitrary code execution. The vulnerability was reported by a team of researchers and fixed in Firefox 148 and Firefox ESR 140.8. The vendor advisory confirms the fix and categorizes the impact as high. The vulnerability is part of a broader set of memory safety issues addressed in the same release cycle.
Potential Impact
Successful exploitation of this use-after-free vulnerability could result in arbitrary code execution with the privileges of the user running Firefox. This can lead to complete compromise of the affected system. The CVSS v3.1 score is 9.8 (critical), reflecting network attack vector, no required privileges or user interaction, and high confidentiality, integrity, and availability impacts.
Mitigation Recommendations
Mozilla has released official fixes for this vulnerability in Firefox 148 and Firefox ESR 140.8. Users and administrators should update affected Firefox installations to these versions or later to remediate the issue. No additional mitigation steps are required beyond applying the official update.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-02-19T15:05:37.180Z
- Cvss Version
- null
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-13/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-15/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-16/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-17/","vendor":"Mozilla"},{"url":"https://access.redhat.com/security/cve/CVE-2026-2766","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3984","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3976","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:4260","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3361","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3517","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3338","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3515","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3492","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:4432","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3491","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3980","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3495","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3979","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3494","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:4022","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3493","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3983","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:4152","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3978","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3496","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3981","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3497","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3982","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3339","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:3516","vendor":"Red Hat"}]
Threat ID: 699daf6dbe58cf853bdde173
Added to database: 02/24/2026, 14:02:21 UTC
Last enriched: 07/15/2026, 08:11:22 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 177
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