CVE-2026-16363

JIT miscompilation in the JavaScript: WebAssembly component

Published Jul 21, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed
Description
JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4695-1 firefox-esr security update
Debian DLA Debian DLA DLA-4727-1 thunderbird security update
Debian DSA Debian DSA DSA-6394-1 firefox-esr security update
Debian DSA Debian DSA DSA-6418-1 thunderbird security update
History
Type Values Removed Values Added
Description JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 153 and Firefox ESR 140.13. JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
References
Type Values Removed Values Added
Weaknesses CWE-682
CWE-843
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox
Type Values Removed Values Added
Description JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 153 and Firefox ESR 140.13.
Title JIT miscompilation in the JavaScript: WebAssembly component
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
Jul 22, 2026, 7:18 PM
Reserved
Jul 20, 2026, 9:56 PM
Status
Analyzed
Published
Jul 21, 2026, 1:17 PM
Modified
Oct 24, 2026, 8:10 PM
Severity
Important
Public date
Jul 21, 2026, 12:37 PM