CVE-2021-42248 : Security Advisory and Response

GJSON <= 1.9.2 allows attackers to cause a redos via crafted JSON input.

Understanding CVE-2021-42248

This CVE identifies a vulnerability in GJSON version 1.9.2 and below that can be exploited by attackers for denial of service through specially crafted JSON input.

What is CVE-2021-42248?

GJSON version 1.9.2 and earlier are susceptible to a Regular Expression Denial of Service (ReDoS) attack when processing malicious JSON data.

The Impact of CVE-2021-42248

The vulnerability can be exploited by malicious actors to cause denial of service, potentially impacting the availability of systems or services utilizing GJSON.

Technical Details of CVE-2021-42248

This section delves into the specifics of the vulnerability.

Vulnerability Description

The issue arises from the inadequate handling of JSON input, enabling attackers to construct payloads that trigger excessive computation time during parsing, leading to a denial of service condition.

Affected Systems and Versions

GJSON versions up to 1.9.2 are impacted.

Exploitation Mechanism

Attackers can exploit this vulnerability by providing specially crafted JSON input, causing excessive computation time and resource consumption during parsing.

Mitigation and Prevention

Mitigation strategies and best practices to address the CVE.

Immediate Steps to Take

Update GJSON to version 1.9.3 or later to mitigate the vulnerability.
Use input validation mechanisms to prevent the introduction of crafted JSON payloads.

Long-Term Security Practices

Regularly monitor for updates and patches for GJSON and other dependencies.
Implement secure coding practices and input validation to mitigate similar vulnerabilities in the future.

Patching and Updates

Apply patches and updates provided by the GJSON project to remediate the vulnerability.