CVE-2025-43575: Critical Out-of-bounds Write Vulnerability in Acrobat Reader

Overview

This blog post delves into an out-of-bounds vulnerability, identified as CVE-2025-43575, that affects multiple versions of Acrobat Reader. This is a critical issue as Acrobat Reader is a widely-used software for viewing, creating, manipulating, printing, and managing files in Portable Document Format (PDF). The vulnerability, if exploited, allows for arbitrary code execution, thereby putting a significant number of systems and data at risk. It’s imperative that users and administrators understand this vulnerability and implement recommended mitigation strategies.

Vulnerability Summary

CVE ID: CVE-2025-43575
Severity: High (CVSS score 7.8)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions

Acrobat Reader | 24.001.30235
Acrobat Reader | 20.005.30763
Acrobat Reader | 25.001.20521 and earlier

How the Exploit Works

The vulnerability stems from an out-of-bounds write issue in the affected versions of Acrobat Reader. In essence, the software does not properly handle certain inputs, leading to a buffer overflow. This allows a malicious user to write data beyond the allocated memory buffer, potentially leading to code execution. However, for the exploit to be successful, a user must interact with a malicious file-such as opening a manipulated PDF document. This action, in turn, allows the attacker to execute arbitrary code in the context of the current user.

Conceptual Example Code

A conceptual exploit might involve a PDF file that contains malicious code. When the user opens the file with a vulnerable version of Acrobat Reader, the out-of-bounds write vulnerability is triggered, and the malicious code is executed. Here is a pseudocode example:

Open PDF file
if Acrobat Reader version is vulnerable
trigger out-of-bounds write vulnerability
execute arbitrary code
end if
Close PDF file

Note: This is a simplified representation and actual exploits would be far more complex and obfuscated to avoid detection by security software.

Mitigation Guidance

Users are strongly advised to apply the vendor-provided patch to mitigate this vulnerability. If a patch cannot be applied immediately, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation measure. However, these measures do not fully resolve the issue and only help to reduce the risk of exploitation. As such, applying the vendor patch should be a priority.