Mozilla Firefox <149 JIT Miscompilation in JS Engine (CVE-2026-4702)
CVE-2026-4702 Published on March 24, 2026
JIT miscompilation in the JavaScript Engine component
JIT miscompilation in the JavaScript Engine component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
Vulnerability Analysis
CVE-2026-4702 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
Weakness Type
What is an Object Type Confusion Vulnerability?
The program allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.
CVE-2026-4702 has been classified to as an Object Type Confusion vulnerability or weakness.
Products Associated with CVE-2026-4702
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Affected Versions
Mozilla Firefox:- Version unspecified and below 149 is affected.
- Version unspecified and below 140.9 is affected.
- Version unspecified and below 149 is affected.
- Version unspecified and below 140.9 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.