CVE-2025-14330: CRITICAL Severity JIT Miscompilation in Firefox and Thunderbird | Secably CVE Database

Summary

CVE-2025-14330 is a critical severity vulnerability affecting Mozilla Firefox and Thunderbird. This vulnerability stems from a JIT (Just-In-Time) miscompilation within the JavaScript Engine, potentially leading to arbitrary code execution. Successful exploitation could allow an attacker to compromise the affected system.

Technical Details

CVE-2025-14330 describes a JIT miscompilation vulnerability within the JavaScript Engine's JIT component. The JIT compiler, responsible for optimizing JavaScript code execution, incorrectly compiles certain code sequences. This miscompilation can lead to unexpected behavior, memory corruption, and ultimately, the ability to execute arbitrary code. The root cause lies in a flaw in the JIT compiler's logic when handling specific JavaScript constructs. An attacker could craft malicious JavaScript code designed to trigger this miscompilation, leading to a controlled crash or arbitrary code execution within the context of the browser or email client. The complexity of the JIT compiler and the subtle nature of the miscompilation make this a challenging vulnerability to identify and exploit.

The vulnerability resides in the way the JIT compiler handles specific data types or operations. When the compiler encounters these specific conditions, it generates incorrect machine code, leading to memory corruption or other unexpected behavior. This incorrect code can then be leveraged by an attacker to gain control of the execution flow and ultimately execute arbitrary code.

Affected Products and Versions

The following products and versions are affected by CVE-2025-14330:

Mozilla Firefox versions prior to 146
Mozilla Firefox ESR versions prior to 140.6
Mozilla Thunderbird versions prior to 146
Mozilla Thunderbird versions prior to 140.6

Users of these products are strongly advised to upgrade to the latest versions as soon as possible.

Impact Assessment

Successful exploitation of CVE-2025-14330 can have severe consequences. An attacker could potentially execute arbitrary code on the affected system, leading to:

Complete system compromise
Data theft and exfiltration
Installation of malware
Denial-of-service attacks
Remote code execution

Due to the critical nature of this vulnerability, immediate patching is highly recommended.

Remediation

The primary remediation for CVE-2025-14330 is to update the affected Mozilla Firefox and Thunderbird installations to the latest versions.

Immediate Actions

Update Firefox: Upgrade to Firefox version 146 or later.
Update Firefox ESR: Upgrade to Firefox ESR version 140.6 or later.
Update Thunderbird: Upgrade to Thunderbird version 146 or later.
Update Thunderbird ESR: Upgrade to Thunderbird ESR version 140.6 or later.
Verify Updates: Ensure the updates have been successfully installed by checking the version number in the application's 'About' section.

Long-term Solutions

Enable Automatic Updates: Configure Firefox and Thunderbird to automatically install updates to ensure timely patching of future vulnerabilities.
Security Awareness Training: Educate users about the risks of clicking on suspicious links or opening attachments from unknown sources.

References

The following resources provide additional information about CVE-2025-14330:

Detection & Scanning

Detecting CVE-2025-14330 typically involves identifying vulnerable versions of Firefox and Thunderbird. Security scanners and vulnerability assessment tools can be used to identify systems running affected versions. Network intrusion detection systems (IDS) may also be configured to detect suspicious activity indicative of exploitation attempts.

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