CVE-2023-22240 in Acrobat Reader
Summary
by MITRE • 01/27/2023
Adobe Acrobat Reader versions 22.003.20282 (and earlier), 22.003.20281 (and earlier) and 20.005.30418 (and earlier) are affected by an out-of-bounds write vulnerability that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
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Analysis
by VulDB Data Team • 09/27/2025
Adobe Acrobat Reader contains a critical out-of-bounds write vulnerability that allows attackers to execute arbitrary code when a user opens a maliciously crafted file. This vulnerability exists in multiple versions including 22.003.20282 and earlier, 22.003.20281 and earlier, and 20.005.30418 and earlier. The flaw occurs during the processing of specially crafted PDF files that trigger an out-of-bounds memory write operation, potentially allowing attackers to overwrite adjacent memory locations with malicious data. The vulnerability requires user interaction to exploit, meaning victims must willingly open the malicious file, typically through social engineering tactics such as phishing emails or compromised websites. This type of vulnerability falls under CWE-787 Out-of-bounds Write, which is classified as a critical security weakness in the Common Weakness Enumeration catalog. The attack vector aligns with ATT&CK technique T1203 Exploitation for Client Execution, where adversaries leverage software vulnerabilities to execute malicious code on target systems. When successfully exploited, this vulnerability could enable attackers to gain full control of the affected system, potentially leading to data theft, persistent backdoor installation, or further network infiltration. The impact is particularly severe because Adobe Acrobat Reader is widely deployed across enterprise environments and individual workstations, making it an attractive target for cybercriminals seeking to compromise user systems. The out-of-bounds write condition typically occurs when the application fails to properly validate input data from PDF files, specifically during parsing of malformed or crafted objects within the document structure. This vulnerability represents a significant risk to organizations that rely heavily on PDF document processing, as it can be exploited through various attack vectors including email attachments, web downloads, and document sharing platforms. The exploitation process requires careful crafting of malicious PDF content that can trigger the memory corruption without immediate detection, making it particularly dangerous for enterprise security environments where users frequently interact with external documents.
The technical nature of this vulnerability stems from improper bounds checking within Adobe Acrobat Reader's PDF parsing engine. When processing malicious PDF files, the application does not adequately validate array indices or buffer boundaries, leading to memory corruption that can be leveraged for code execution. This flaw represents a classic buffer overflow scenario where attacker-controlled data can overwrite adjacent memory regions, potentially allowing the execution of arbitrary code with the privileges of the current user. The vulnerability's exploitation requires a victim to open a specifically crafted PDF file, which typically occurs through social engineering campaigns targeting end users. Security researchers have identified that the vulnerability manifests when the application attempts to write data beyond the allocated memory buffer, often during the rendering or parsing of complex PDF objects such as embedded images, fonts, or JavaScript elements. The out-of-bounds write condition creates an opportunity for attackers to inject malicious code into the application's memory space, potentially enabling privilege escalation or persistent access to the compromised system. This vulnerability is particularly concerning due to Adobe Reader's widespread deployment and the fact that many users do not receive adequate security training to identify potentially malicious documents. The exploitability factor is moderate to high, as it requires only user interaction rather than sophisticated attack infrastructure, making it accessible to threat actors with basic technical skills.
Organizations and individuals must implement immediate mitigation strategies to protect against exploitation of this vulnerability. The most effective immediate action is to update Adobe Acrobat Reader to the latest version, which includes patches addressing the out-of-bounds write flaw. Security teams should prioritize patch management for all affected systems and establish monitoring for suspicious PDF file activity. Additional defensive measures include implementing email filtering solutions that can detect and block malicious PDF attachments, configuring application whitelisting policies to restrict execution of untrusted PDF files, and deploying endpoint detection and response solutions that can identify suspicious memory access patterns. Network-based defenses such as web application firewalls and content inspection systems can help prevent users from accessing malicious PDF files through web browsers or document sharing platforms. Organizations should also consider implementing user education programs to raise awareness about phishing campaigns that may deliver malicious PDF files. The vulnerability's classification as a critical issue means that organizations should treat it with high priority in their vulnerability management processes, as exploitation could lead to complete system compromise. Security teams should monitor threat intelligence feeds for indicators of compromise related to this vulnerability and prepare incident response plans that account for potential exploitation scenarios. Regular security assessments should include verification that all Adobe Acrobat Reader installations have been updated to secure versions, and automated scanning tools should be deployed to identify any remaining vulnerable systems within the organization's infrastructure.
The vulnerability's impact extends beyond individual user systems to enterprise networks where Adobe Acrobat Reader is commonly used for document review and collaboration. In enterprise environments, this vulnerability could enable attackers to gain access to sensitive business documents, internal network resources, or proprietary information stored in PDF format. The out-of-bounds write condition creates a persistent threat vector that attackers can leverage for extended periods, potentially allowing for data exfiltration, lateral movement, or establishment of command and control channels. Organizations with legacy systems or restricted update capabilities should implement additional compensating controls such as sandboxing solutions that isolate PDF processing or network segmentation that limits access to sensitive systems. The vulnerability also highlights the importance of maintaining current security patches across all software applications, as Adobe Acrobat Reader represents just one example of how widely used applications can contain critical security flaws. Security professionals should consider this vulnerability as part of broader risk assessments that evaluate the attack surface of commonly used productivity software. The remediation process requires not only updating the software but also validating that the update was successful and monitoring for any signs of exploitation attempts. Organizations should maintain detailed logs of PDF file access and processing activities to aid in forensic analysis should exploitation occur, ensuring that incident response teams have adequate information to assess the scope and impact of potential breaches.