CVE-2025-43573: Acrobat Reader Use After Free Vulnerability Leading to Arbitrary Code Execution

Overview

In the ever-changing landscape of cybersecurity, vulnerabilities are constantly being discovered and patched. One such vulnerability that has come to light is CVE-2025-43573, affecting several versions of Acrobat Reader, a widely used software across the globe. This vulnerability could lead to arbitrary code execution, potentially compromising user systems or leading to unauthorized data leakage. Given the ubiquity of Acrobat Reader, this vulnerability could have a wide-ranging impact, necessitating immediate attention and mitigation.

Vulnerability Summary

CVE ID: CVE-2025-43573
Severity: High (CVSS Score: 7.8)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Arbitrary code execution potentially leading to system compromise or data leakage

Affected Products

Product | Affected Versions

Acrobat Reader | 24.001.30235
Acrobat Reader | 20.005.30763
Acrobat Reader | 25.001.20521

How the Exploit Works

The CVE-2025-43573 vulnerability arises due to a ‘Use After Free’ flaw in the affected versions of Acrobat Reader. In essence, this means that the software continues to use memory after it has been freed or deleted. This can lead to unexpected behavior, including the execution of arbitrary code.
In the case of this vulnerability, an attacker would have to craft a malicious file, which when opened by a victim using the vulnerable versions of Acrobat Reader, would trigger the flaw and allow the attacker to execute arbitrary code in the context of the current user. This could potentially result in a full system compromise or unauthorized data leakage.

Conceptual Example Code

Here is a conceptual example of how an attacker might craft a malicious PDF to exploit this vulnerability:

# pseudo python code to create a malicious PDF
import PyPDF2
# Create a PDF object
malicious_pdf = PyPDF2.PdfFileWriter()
# Add malicious payload
payload = """
<insert malicious code here that triggers Use After Free vulnerability>
"""
malicious_pdf.addPage(payload)
# Save the PDF
with open("malicious.pdf", "wb") as f:
malicious_pdf.write(f)

In this pseudo-code example, the attacker crafts a malicious PDF that contains the code to trigger the ‘Use After Free’ vulnerability when opened in the vulnerable version of Acrobat Reader. The actual payload would be specific to the vulnerability and the attacker’s intended outcome (e.g., arbitrary code execution, data exfiltration).
Please note that the above is a conceptual example and is not intended to be used for malicious purposes. As a cybersecurity professional, it is our responsibility to understand these vulnerabilities to better protect our systems and data, not to exploit them.