CVE-2021-39861 Explained : Impact and Mitigation

Adobe Acrobat Reader DC versions 2021.005.20060, 2020.004.30006, and 2017.011.30199 are affected by an out-of-bounds read vulnerability that could disclose arbitrary memory information.

Understanding CVE-2021-39861

This CVE involves an out-of-bounds read vulnerability in Adobe Acrobat Reader DC versions, potentially leading to information disclosure.

What is CVE-2021-39861?

Vulnerability Type: Out-of-bounds Read (CWE-125)
CVSS Base Score: 5.5 (Medium)
CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Attack Complexity: Low, Attack Vector: Local, User Interaction: Required

The Impact of CVE-2021-39861

The vulnerability could result in the disclosure of arbitrary memory information within the context of the current user when a malicious file is opened.

Technical Details of CVE-2021-39861

This section provides detailed technical aspects of the vulnerability.

Vulnerability Description

Affected Software: Acrobat Reader DC
Versions: 2021.005.20060, 2020.004.30006, 2017.011.30199
Description: Out-of-bounds read vulnerability

Affected Systems and Versions

Affected Product: Adobe Acrobat Reader
Versions at Risk: <= 2021.005.20060, <= 2020.004.30006, <= 2017.011.30199

Exploitation Mechanism

The exploitation of this issue requires user interaction, where a victim must open a file containing the malicious code.

Mitigation and Prevention

Ways to address and prevent the CVE-2021-39861 vulnerability.

Immediate Steps to Take

Update to the latest unaffected version
Exercise caution while opening files from unknown or untrusted sources

Long-Term Security Practices

Regularly update the software to patch vulnerabilities
Implement user training on recognizing and avoiding suspicious files

Patching and Updates

Check for and apply security patches provided by Adobe
Stay informed about security bulletins and updates from the vendor