CVE-2026-12321: Vulnerability in Mozilla Firefox
CVE-2026-12321 is a low-impact vulnerability involving JIT miscompilation in the JavaScript WebAssembly component of Mozilla Firefox. This issue was fixed in Firefox version 152. The vulnerability is part of a broader set of security fixes released in Firefox 152 and Thunderbird 152 addressing multiple memory safety bugs, sandbox escapes, and other issues. The CVSS score for this specific vulnerability is 5.4 (medium severity), but the vendor rates its impact as low. No known exploits are reported in the wild. Users running Firefox versions prior to 152 are affected.
AI Analysis
Technical Summary
This vulnerability involves a Just-In-Time (JIT) miscompilation flaw in the JavaScript WebAssembly component of Mozilla Firefox, identified as CVE-2026-12321. It was fixed in Firefox 152. The issue is part of a large batch of security vulnerabilities addressed in Firefox 152 and Thunderbird 152, which include multiple memory safety bugs, sandbox escapes, and other security flaws. The CVSS v3.1 base score is 5.4, reflecting a medium severity with network attack vector, low attack complexity, no privileges required, user interaction required, unchanged scope, and low confidentiality and integrity impacts. The Mozilla advisory confirms the fix in Firefox 152 and Thunderbird 152. No exploits in the wild have been reported for this vulnerability.
Potential Impact
The vulnerability could lead to limited confidentiality and integrity impacts due to JIT miscompilation in the JavaScript WebAssembly component. However, the vendor rates the impact as low for this specific issue. There are no known exploits in the wild. The vulnerability affects Firefox versions prior to 152. The broader set of vulnerabilities fixed in Firefox 152 includes some high-impact issues, but CVE-2026-12321 itself is considered low impact.
Mitigation Recommendations
A fix for this vulnerability is available in Mozilla Firefox version 152. Users and administrators should update affected Firefox installations to version 152 or later to remediate this issue. The vendor advisory confirms the official fix. No additional mitigation actions are required beyond applying the update.
CVE-2026-12321: Vulnerability in Mozilla Firefox
Description
CVE-2026-12321 is a low-impact vulnerability involving JIT miscompilation in the JavaScript WebAssembly component of Mozilla Firefox. This issue was fixed in Firefox version 152. The vulnerability is part of a broader set of security fixes released in Firefox 152 and Thunderbird 152 addressing multiple memory safety bugs, sandbox escapes, and other issues. The CVSS score for this specific vulnerability is 5.4 (medium severity), but the vendor rates its impact as low. No known exploits are reported in the wild. Users running Firefox versions prior to 152 are affected.
CVSS v3.1
Score 5.4medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves a Just-In-Time (JIT) miscompilation flaw in the JavaScript WebAssembly component of Mozilla Firefox, identified as CVE-2026-12321. It was fixed in Firefox 152. The issue is part of a large batch of security vulnerabilities addressed in Firefox 152 and Thunderbird 152, which include multiple memory safety bugs, sandbox escapes, and other security flaws. The CVSS v3.1 base score is 5.4, reflecting a medium severity with network attack vector, low attack complexity, no privileges required, user interaction required, unchanged scope, and low confidentiality and integrity impacts. The Mozilla advisory confirms the fix in Firefox 152 and Thunderbird 152. No exploits in the wild have been reported for this vulnerability.
Potential Impact
The vulnerability could lead to limited confidentiality and integrity impacts due to JIT miscompilation in the JavaScript WebAssembly component. However, the vendor rates the impact as low for this specific issue. There are no known exploits in the wild. The vulnerability affects Firefox versions prior to 152. The broader set of vulnerabilities fixed in Firefox 152 includes some high-impact issues, but CVE-2026-12321 itself is considered low impact.
Mitigation Recommendations
A fix for this vulnerability is available in Mozilla Firefox version 152. Users and administrators should update affected Firefox installations to version 152 or later to remediate this issue. The vendor advisory confirms the official fix. No additional mitigation actions are required beyond applying the update.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-06-15T15:08:19.456Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-57/","vendor":"Mozilla"}]
Threat ID: 6a314c830b89be6888b4cdca
Added to database: 06/16/2026, 13:15:47 UTC
Last enriched: 06/23/2026, 15:19:40 UTC
Last updated: 07/31/2026, 19:22:57 UTC
Views: 98
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