CVE-2026-79907 in Acrobat Reader
Summary
by MITRE • 09/09/2026
Acrobat Reader is affected by a Double 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 • 09/09/2026
The Adobe Acrobat Reader application contains a critical memory management flaw classified as a double free vulnerability, which poses a severe risk to system integrity and confidentiality. This specific type of error occurs when the software attempts to deallocate a block of memory that has already been freed by a previous operation within the same execution context. In standard programming practices, freeing memory twice leads to undefined behavior because the first deallocation typically returns the pointer to the operating system's heap manager for potential reuse or marks it as invalid depending on the allocator implementation. When the second free call is executed against this now-invalid or reused pointer, it corrupts the internal data structures of the memory allocator. This corruption can manifest in various ways, but most critically, it allows an attacker to manipulate how subsequent memory allocations are handled, thereby gaining control over critical program flow and data pointers.
From a technical perspective, this vulnerability falls under the Common Weakness Enumeration category CWE-415, which defines double free as freeing the same pointer more than once. The exploitation of such flaws relies heavily on heap spraying techniques or specific allocation patterns that allow an attacker to predict where their malicious payload will be placed in memory after the corrupted allocator returns a controlled address. By carefully crafting the input data within a PDF document, an adversary can trigger this sequence of events during the parsing and rendering process. The vulnerability is particularly dangerous because it resides in one of the most widely deployed software applications for viewing documents on Windows, macOS, and Linux platforms. The complexity of modern memory allocators makes exploiting double free vulnerabilities challenging but not impossible for skilled attackers who utilize advanced heap grooming techniques to stabilize the exploit state before achieving code execution.
The operational impact of successfully exploiting this vulnerability is catastrophic, resulting in arbitrary code execution within the security context of the current user. This means that if a victim opens a specially crafted malicious PDF file, the attacker can execute any command or program on the compromised system with the same privileges as the logged-in user. In typical desktop environments where users operate with administrative rights or standard user accounts without strict sandboxing, this level of access allows for complete system compromise. The attacker could install backdoors, steal sensitive data such as credentials and financial information, pivot to other systems within a network, or establish persistent control over the machine. Since Adobe Acrobat Reader is often used in enterprise environments to view contracts, reports, and legal documents, it represents a high-value target for phishing campaigns and targeted attacks aimed at corporate espionage or ransomware deployment.
Mitigation strategies must address both immediate remediation and long-term defensive posture improvements. The primary defense is the prompt application of vendor-provided security patches that correct the memory management logic to prevent double deallocation. Organizations should enforce automated patch management policies to ensure all endpoints have the latest version of Adobe Acrobat Reader installed. Additionally, since exploitation requires user interaction through opening a malicious file, implementing strict email filtering and web proxy solutions can help block access to known malicious URLs or attachments containing exploit code. Endpoint Detection and Response (EDR) tools configured with behavioral monitoring rules specific to memory corruption attacks can also detect anomalous heap activity indicative of double free exploits in real-time. Furthermore, enabling Protected Mode within Adobe Acrobat Reader restricts the application's ability to write to critical system areas, thereby limiting the impact even if an exploit succeeds. Regular security awareness training for employees is equally vital to reduce the likelihood of users opening untrusted documents that may contain such vulnerabilities.