CVE-2021-37220 : What You Need to Know
Learn about CVE-2021-37220, an out-of-bounds write vulnerability in MuPDF through 1.18.1. Understand the impact, technical details, affected systems, and mitigation steps.
MuPDF through 1.18.1 is impacted by an out-of-bounds write vulnerability due to improper consideration of the maximum key size of a hash table within the cached color converter. This flaw can be exploited through crafted "mutool draw" input.
Understanding CVE-2021-37220
This section delves into the details of the CVE-2021-37220 vulnerability.
What is CVE-2021-37220?
CVE-2021-37220 refers to an out-of-bounds write vulnerability in MuPDF through version 1.18.1. The issue arises from the inadequacy in considering the maximum key size of a hash table in the color converter caching mechanism.
The Impact of CVE-2021-37220
Exploitation of this vulnerability could lead to a security breach or a denial of service (DoS) attack. Attackers may leverage crafted inputs to trigger the out-of-bounds write, potentially resulting in arbitrary code execution or system crashes.
Technical Details of CVE-2021-37220
This section outlines the technical aspects of CVE-2021-37220.
Vulnerability Description
The vulnerability manifests as an out-of-bounds write caused by the color converter's improper handling of hash table key sizes. Crafted inputs to the "mutool draw" utility can be used to exploit this weakness.
Affected Systems and Versions
MuPDF versions up to and including 1.18.1 are affected by this vulnerability.
Exploitation Mechanism
Attackers can exploit this vulnerability by supplying malicious inputs through the "mutool draw" functionality, causing an out-of-bounds write within the color converter's caching mechanism.
Mitigation and Prevention
Understanding how to mitigate and prevent the exploitation of CVE-2021-37220 is crucial in maintaining system security.
Immediate Steps to Take
It is recommended to update MuPDF to a patched version beyond 1.18.1 to mitigate the vulnerability. Additionally, users should avoid processing untrusted or suspicious PDF files.
Long-Term Security Practices
In the long term, organizations should implement secure coding practices, conduct regular security audits, and stay informed about software vulnerabilities to enhance overall security posture.
Patching and Updates
Regularly applying security patches and updates to MuPDF and other software components is essential to address known vulnerabilities and protect systems against potential exploits.