CVE-2021-39838 : Security Advisory and Response

Adobe Acrobat Reader DC versions 2021.005.20060 and earlier are affected by a use-after-free vulnerability in the processing of the AcroForm buttonGetCaption action.

Understanding CVE-2021-39838

This CVE involves a critical vulnerability in Adobe Acrobat Reader DC that could lead to remote code execution.

What is CVE-2021-39838?

Acrobat Reader DC versions 2021.005.20060 and earlier are susceptible to a use-after-free flaw in the processing of the AcroForm buttonGetCaption action, potentially allowing arbitrary code execution.

The Impact of CVE-2021-39838

The vulnerability has a CVSS base score of 7.8, indicating a high severity issue with significant impact on confidentiality, integrity, and availability.

Technical Details of CVE-2021-39838

Adobe Acrobat Reader DC is affected by the following:

Vulnerability Description

A use-after-free vulnerability in the AcroForm buttonGetCaption action could result in arbitrary code execution within the context of the current user.

Affected Systems and Versions

Adobe Acrobat Reader DC versions 2021.005.20060 and earlier
Versions 2020.004.30006 and earlier
Versions 2017.011.30199 and earlier

Exploitation Mechanism

Exploitation requires user interaction by opening a malicious file.

Mitigation and Prevention

Immediate actions and long-term security practices:

Immediate Steps to Take

Update Adobe Acrobat Reader DC to the latest patched version.
Be cautious while opening PDF files from unknown or untrusted sources.

Long-Term Security Practices

Regularly check for security updates and apply them promptly.
Educate users on safe browsing practices and cautious file handling.

Patching and Updates

Adobe has released patches to address this vulnerability. Ensure all systems are updated to the patched version.