CVE-2026-78513 in Office
Summary
by MITRE • 09/09/2026
Out-of-bounds read in Microsoft Office PowerPoint allows an unauthorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as an out-of-bounds read within Microsoft Office PowerPoint represents a critical memory safety flaw that compromises the confidentiality of data on affected systems. This specific type of error occurs when software attempts to access memory locations beyond the boundaries of allocated buffers, typically due to insufficient validation of input parameters or improper handling of array indices. In the context of PowerPoint, this likely involves the processing of complex presentation files containing embedded objects, media elements, or specialized formatting structures that trigger malformed parsing logic within the application's rendering engine. When an attacker crafts a malicious document with specifically designed content, they can exploit this boundary violation to cause the application to read from memory regions it is not authorized to access.
From a technical perspective, out-of-bounds reads are classified under CWE-125, which describes situations where software reads data past the end or before the beginning of the intended buffer. Unlike out-of-bounds writes, which can lead to code execution and remote control of the system, out-of-bounds reads primarily result in information disclosure. The attacker does not gain direct command execution capabilities through this flaw alone but rather leverages the unintended memory access to extract sensitive data residing in adjacent memory spaces. This could include partial contents of other open documents, cached credentials, encryption keys, or internal application state variables that were previously loaded into memory for processing.
The operational impact of this vulnerability is significant because it allows an unauthorized attacker to disclose information locally without requiring elevated privileges on the target machine. The attack vector typically involves tricking a user into opening a specially crafted PowerPoint file, which aligns with common social engineering tactics used in targeted attacks. Once opened, the malicious document triggers the parsing routine that contains the flaw, causing PowerPoint to leak memory contents back to the attacker through side-channel effects or by corrupting subsequent operations in ways that reveal data patterns. This local information disclosure can serve as a stepping stone for further exploitation, such as bypassing security controls like Data Execution Prevention (DEP) or Address Space Layout Randomization (ASLR), although these are secondary risks compared to the primary confidentiality breach.
In terms of threat intelligence frameworks, this vulnerability maps closely to MITRE ATT&CK technique T1005, which covers Data from Local System Retrieval. Attackers utilize such vulnerabilities to gather reconnaissance data that aids in lateral movement or privilege escalation within an enterprise environment. The ability to read arbitrary memory locations provides valuable insights into the system's configuration and active processes, enabling adversaries to tailor subsequent attacks more effectively against high-value targets protected by robust perimeter defenses.
Mitigation strategies for this vulnerability focus on both immediate remediation and long-term architectural improvements. Organizations should immediately apply the latest security updates provided by Microsoft, which contain patches that enforce stricter bounds checking during file parsing operations. These patches typically involve adding validation checks to ensure that all memory accesses remain within allocated limits before proceeding with data processing. Additionally, implementing application whitelisting solutions can prevent unauthorized or untrusted PowerPoint files from executing arbitrary code paths associated with the vulnerability. Users should be educated on recognizing suspicious attachments and avoiding opening documents from unknown sources, as this remains a primary defense against exploitation attempts that rely on social engineering to trigger the initial parsing routine.