Use-After-Free in Firefox JS Engine (<v149)
CVE-2026-4723 Published on March 24, 2026
Use-after-free in the JavaScript Engine component
Use-after-free in the JavaScript Engine component. This vulnerability affects Firefox < 149 and Thunderbird < 149.
Vulnerability Analysis
CVE-2026-4723 can be exploited 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 a Dangling pointer Vulnerability?
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
CVE-2026-4723 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-4723
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Affected Versions
Mozilla Firefox:- Version unspecified and below 149 is affected.
- Version unspecified and below 149 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.