CVE-2021-31875 : What You Need to Know

A heap-based buffer overflow vulnerability in Cesanta MongooseOS mJS 1.26 can be triggered by a maliciously crafted JSON string, potentially allowing for control flow redirection. Despite some disputes over the severity of this issue, it is essential to understand the risks and mitigation strategies.

Understanding CVE-2021-31875

This section will delve into the nature of the CVE-2021-31875 vulnerability to provide a comprehensive understanding of its implications.

What is CVE-2021-31875?

CVE-2021-31875 involves an off-by-one heap-based buffer overflow in mjs_json_parse functionality of Cesanta MongooseOS mJS 1.26. This can be exploited by a specially crafted JSON string to potentially redirect control flow.

The Impact of CVE-2021-31875

While the severity is disputed, any buffer overflow vulnerability poses a risk of exploitation, leading to unauthorized control flow redirection and possibly security compromises.

Technical Details of CVE-2021-31875

This section will discuss the technical aspects of the CVE-2021-31875 vulnerability, including affected systems, exploitation mechanisms, and more.

Vulnerability Description

The vulnerability arises from an off-by-one heap-based buffer overflow in the mjs_json_parse function, triggered by a malicious JSON string.

Affected Systems and Versions

The affected system is Cesanta MongooseOS mJS 1.26. All prior versions may also be vulnerable to this exploit.

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting a malicious JSON string to trigger the buffer overflow, potentially leading to control flow redirection.

Mitigation and Prevention

To safeguard against CVE-2021-31875, immediate steps must be taken alongside adopting long-term security practices and ensuring the application of necessary patches and updates.

Immediate Steps to Take

Developers and users should exercise caution when handling JSON input, validate user input, and consider input size limitations to prevent buffer overflow vulnerabilities.

Long-Term Security Practices

Implement secure coding practices, conduct regular security assessments, and stay informed about potential vulnerabilities to enhance overall system security.

Patching and Updates

It is crucial to update to the latest version of Cesanta MongooseOS mJS and apply patches released by the vendor to mitigate the CVE-2021-31875 vulnerability.