CVE-2023-26422 in Acrobat Reader
Summary
by MITRE • 04/13/2023
Adobe Acrobat Reader versions 23.001.20093 (and earlier) and 20.005.30441 (and earlier) are affected by a Use After Free 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 • 11/09/2025
Adobe Acrobat Reader remains a widely deployed application for document processing across enterprise and consumer environments, making vulnerabilities within its codebase particularly concerning from a cybersecurity perspective. The specific vulnerability identified as CVE-2023-26422 represents a use after free condition that occurs when the application handles certain malformed PDF files. This type of vulnerability falls under the CWE-416 category, which specifically addresses the use of freed memory, and aligns with the broader class of memory safety issues that have historically led to remote code execution exploits. The vulnerability exists in versions 23.001.20093 and earlier, as well as 20.005.30441 and earlier, indicating a persistent flaw that spans multiple release lines of the software.
The technical mechanism behind this vulnerability involves the application's improper handling of memory management during PDF parsing operations. When processing maliciously crafted PDF documents, the Acrobat Reader engine allocates memory for certain objects and subsequently frees that memory without proper validation. An attacker can manipulate the document structure to cause the application to access this freed memory location, potentially leading to arbitrary code execution. This particular flaw requires user interaction to be exploited, meaning that a victim must actively open the malicious file, which aligns with the attack pattern described in the ATT&CK framework under T1203 - Exploitation for Client Execution. The attack vector is therefore limited to social engineering campaigns where users are tricked into opening specifically crafted documents.
The operational impact of this vulnerability extends beyond simple code execution as it represents a critical escalation path for attackers seeking to compromise systems running vulnerable versions of Adobe Acrobat Reader. Since the exploit requires user interaction, it typically manifests through phishing campaigns, malicious email attachments, or compromised websites hosting malicious PDF files. The context of execution is particularly dangerous because Acrobat Reader often runs with elevated privileges when processing documents, and the vulnerability can potentially be leveraged to bypass security controls such as application whitelisting. Organizations that rely heavily on PDF document processing for business operations face significant risk exposure, as the attack surface includes not only end-user systems but also shared network resources where PDF files might be accessed through various document management systems.
Mitigation strategies for CVE-2023-26422 should prioritize immediate software updates to versions that have patched the memory management flaw. Adobe has released security updates addressing this vulnerability, and organizations should implement these patches across all affected systems as a priority. Additional protective measures include implementing email filtering solutions that can detect and quarantine potentially malicious PDF attachments, deploying application control policies that restrict execution of Acrobat Reader from untrusted sources, and conducting user awareness training to recognize suspicious document delivery methods. Network-based defenses such as web proxies and content filtering systems can be configured to block access to known malicious PDF hosting sites. From a defensive perspective, this vulnerability highlights the importance of maintaining current security patches and implementing layered security controls, as the use after free condition represents a fundamental memory safety issue that could potentially be exploited in other applications with similar code patterns. The vulnerability also demonstrates how even widely deployed software packages can contain persistent flaws that require continuous monitoring and patch management processes to address effectively.