CVE-2026-55123 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 by unauthorized attackers who can manipulate the application's memory handling during presentation processing. This flaw resides in the way PowerPoint manages memory allocation when parsing specific file formats, particularly those containing maliciously crafted data structures that exceed allocated buffer boundaries. The vulnerability is classified under CWE-121 heap-based buffer overflow which represents a critical weakness in memory management where data written to heap memory can overwrite adjacent memory locations. Attackers exploit this by crafting specially formatted PowerPoint files that trigger the vulnerable code path when opened or processed by the application, allowing them to execute arbitrary code with the privileges of the affected user.
The technical exploitation of this vulnerability occurs through careful manipulation of PowerPoint's parsing routines for slide presentations, embedded objects, or multimedia elements within presentation files. When the vulnerable application attempts to process malformed data structures, it allocates insufficient heap memory for expected content, causing subsequent writes to overflow into adjacent memory regions and potentially overwrite critical program execution pointers or return addresses. This memory corruption directly enables attackers to redirect program flow and inject malicious payloads, making it particularly dangerous in enterprise environments where users frequently open presentations from untrusted sources. The vulnerability affects multiple versions of Microsoft Office PowerPoint and can be triggered through various attack vectors including email attachments, web downloads, or removable media containing crafted presentation files.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data exfiltration capabilities for attackers who successfully exploit it. Organizations face significant risk when users open malicious presentations as the attack requires no special privileges beyond normal user access to execute code locally on target systems. The vulnerability creates persistent threat vectors in environments where presentation files are shared regularly, including corporate networks, educational institutions, and government agencies that rely heavily on PowerPoint for communications and training materials. Security professionals must consider this vulnerability within the broader context of attack chain frameworks such as ATT&CK tactic TA0002 execution and TA0004 privilege escalation, where attackers leverage application weaknesses to establish persistent access and move laterally through networks.
Mitigation strategies should include immediate deployment of Microsoft security patches and updates addressing the specific heap overflow vulnerability in PowerPoint applications. Organizations must implement comprehensive email filtering and web content protection measures to prevent users from accessing potentially malicious presentation files without proper validation. Network segmentation and user access controls can help limit the potential impact of successful exploitation by restricting lateral movement within compromised systems. Security teams should also establish monitoring protocols to detect unusual PowerShell or system command execution patterns that might indicate exploitation attempts, while maintaining regular security awareness training for users to recognize suspicious presentation file attachments. Additionally, implementing application whitelisting policies and disabling unnecessary PowerPoint features can reduce attack surface exposure and provide additional defense layers against this specific vulnerability class.