CVE-2021-41496 Explained : Impact and Mitigation

A buffer overflow vulnerability in NumPy < 1.19 can lead to Denial of Service attacks by manipulating array values.

Understanding CVE-2021-41496

This CVE highlights a disputed buffer overflow issue in NumPy affecting versions prior to 1.19.

What is CVE-2021-41496?

The vulnerability exists in the array_from_pyobj function of fortranobject.c in NumPy < 1.19, enabling attackers to trigger Denial of Service attacks by crafting arrays with negative values. The vendor disputes this as a vulnerability, stating only privileged users can create negative dimensions.

The Impact of CVE-2021-41496

The exploitation of this vulnerability can result in Denial of Service attacks, disrupting system availability and performance.

Technical Details of CVE-2021-41496

This section delves into the specifics of the vulnerability.

Vulnerability Description

The buffer overflow occurs in the array_from_pyobj function of fortranobject.c in NumPy < 1.19, facilitating attackers to exploit negative values to conduct Denial of Service attacks.

Affected Systems and Versions

Affected Version: NumPy < 1.19
All systems using NumPy versions earlier than 1.19 are at risk.

Exploitation Mechanism

Attackers can exploit this vulnerability by constructing arrays with carefully crafted negative values, leading to a buffer overflow and subsequently initiating a Denial of Service attack.

Mitigation and Prevention

Mitigation strategies to address CVE-2021-41496.

Immediate Steps to Take

Update NumPy to version 1.19 or later to mitigate the vulnerability.
Restrict access to privileged users to prevent unauthorized negative dimension creation.

Long-Term Security Practices

Enforce secure coding practices to prevent buffer overflows.
Regularly monitor and update software dependencies to address known vulnerabilities.

Patching and Updates

Apply available patches and updates from NumPy to fix the buffer overflow vulnerability.