Advisory Details

September 16th, 2021

Adobe Acrobat Reader DC AcroForm getItemAt Use-After-Free Remote Code Execution Vulnerability

ZDI-21-1101
ZDI-CAN-14597

CVE ID CVE-2021-39839
CVSS SCORE 7.8, AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
AFFECTED VENDORS Adobe
AFFECTED PRODUCTS Acrobat Reader DC
VULNERABILITY DETAILS

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Adobe Acrobat Reader DC. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the handling of AcroForm fields. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current process.

ADDITIONAL DETAILS Adobe has issued an update to correct this vulnerability. More details can be found at:
https://helpx.adobe.com/security/products/acrobat/apsb21-55.html
DISCLOSURE TIMELINE
  • 2021-08-04 - Vulnerability reported to vendor
  • 2021-09-16 - Coordinated public release of advisory
CREDIT Mark Vincent Yason (@MarkYason)
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