CVE-2026-55043 in Office
Summary
by MITRE • 07/14/2026
Heap-based buffer overflow in Microsoft Office PowerPoint allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 07/15/2026
A heap-based buffer overflow vulnerability exists in Microsoft Office PowerPoint that enables remote code execution when a maliciously crafted file is opened by an unsuspecting user. This critical security flaw resides within the PowerPoint application's handling of specially crafted slide content, particularly affecting how it processes certain multimedia elements and embedded objects. The vulnerability stems from inadequate bounds checking mechanisms in the memory allocation routines used to process presentation files, allowing attackers to overwrite adjacent memory locations on the heap. When a user opens a maliciously crafted pptx or ppsx file, the application attempts to parse the malformed data structure without proper validation, resulting in a buffer overflow condition that can be exploited to inject and execute arbitrary code within the context of the running PowerPoint process. This vulnerability falls under the common weakness enumeration CWE-121 heap-based buffer overflow which is classified as a critical risk due to its potential for remote code execution.
The operational impact of this vulnerability extends beyond simple local privilege escalation as it provides attackers with a powerful vector for initial compromise within enterprise environments where PowerPoint is commonly used. Attackers can leverage this vulnerability through various delivery methods including phishing emails containing malicious attachments, compromised websites serving malicious files, or even through drive-by downloads when users visit compromised web pages. The exploit typically requires minimal user interaction beyond opening the malicious presentation file, making it particularly dangerous in targeted attack scenarios. Security researchers have identified that successful exploitation of this vulnerability can lead to complete system compromise, allowing attackers to install backdoors, steal sensitive data, or establish persistent access to affected systems.
Mitigation strategies for this vulnerability include immediate deployment of Microsoft security patches and updates released through Windows Update or Microsoft Update Catalog, ensuring all users have the latest Office versions with the applicable fixes. Organizations should implement strict email filtering and web proxy configurations to prevent users from accessing potentially malicious PowerPoint files from untrusted sources. Network segmentation and privilege separation can help limit the potential impact if exploitation occurs, while endpoint detection and response solutions should be configured to monitor for suspicious process creation patterns and memory manipulation activities associated with heap-based buffer overflow exploits. According to the mitre att&ck framework this vulnerability aligns with techniques such as initial access through spearphishing attachments and execution through office applications, making it a significant concern for organizations implementing comprehensive threat hunting and incident response procedures. Regular security awareness training for users about suspicious email attachments and presentation files from unknown sources remains crucial in reducing the attack surface and preventing successful exploitation of this vulnerability.
The technical nature of this heap-based buffer overflow demonstrates how seemingly benign application features can become entry points for sophisticated attacks, highlighting the importance of robust input validation and memory safety practices in software development. Organizations should also consider implementing application whitelisting policies to restrict execution of unauthorized Office applications or macros, while monitoring for unusual PowerPoint process behavior that could indicate exploitation attempts. Regular vulnerability assessments and penetration testing focused on office application security can help identify similar weaknesses in other Microsoft Office components that may present comparable risks to the organization's attack surface.