Adobe Acrobat Reader is a widely used tool for viewing, creating, and managing Portable Document Format (PDF) files. Recently, a critical security vulnerability has been discovered in certain versions of the software, identified as CVE-2023-21579. This vulnerability can allow an attacker to execute arbitrary code in the context of the current user. Successful exploitation of this vulnerability requires a user to open a malicious PDF file manually, allowing the attacker to potentially gain control over the affected system.

Affected Versions

Adobe Acrobat Reader versions 22.003.20282 (and earlier), 22.003.20281 (and earlier), and 20.005.30418 (and earlier) are affected by the CVE-2023-21579 vulnerability.

Vulnerability Details

The vulnerability is caused by an Integer Overflow or Wraparound issue in the affected Adobe Acrobat Reader versions. An integer overflow occurs when the result of an arithmetic operation is larger than the maximum value that can be represented in the system. When this happens, the value "wraps around" to the minimum possible value, causing inconsistencies in program behavior and memory allocation. In the case of CVE-2023-21579, this improper memory allocation can be exploited by an attacker to execute arbitrary code in the context of the current user.

Exploit Description

The exploit takes advantage of the integer overflow vulnerability by creating a specially crafted PDF file containing malicious code. When a user opens this malicious PDF file using an affected version of Adobe Acrobat Reader, the code embedded in the document gets executed because of the incorrect memory allocation caused by the integer overflow. The arbitrary code execution occurs in the context of the current user, possibly allowing the attacker to gain control of the affected system.

Code Snippet

Below is a simple example of how an integer overflow can occur in a program. While this is not the actual code used in Adobe Acrobat Reader, it demonstrates the concept of an integer overflow:

#include <stdio.h>
#include <limits.h>

int main() {
  int a = INT_MAX;
  int b = 1;
  int result = a + b;
  printf("a: %d, b: %d, result: %d\n", a, b, result);
  return ;

In this example, the INT_MAX value represents the maximum possible integer value that the system can handle. When the value of a is added to that of b, the result is larger than INT_MAX; hence, an integer overflow occurs. In the context of Adobe Acrobat Reader, such an overflow could lead to memory allocation issues, which can be exploited by an attacker.

Original References



Adobe has released a security update that addresses the CVE-2023-21579 vulnerability. Users of the affected versions should download and install the update as soon as possible to protect their systems from potential attacks. The updated software versions are:


The CVE-2023-21579 vulnerability is a critical security issue affecting Adobe Acrobat Reader. Users of the affected software versions are advised to update their systems immediately to mitigate the risk of arbitrary code execution by an attacker. By promptly applying security patches and practicing cautious behavior when opening PDF files from unknown sources, users can maintain the security and integrity of their systems.


Published on: 01/18/2023 19:15:00 UTC
Last modified on: 01/26/2023 18:14:00 UTC