CVE-2026-55120 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 PowerPoint file is opened by an unsuspecting user. This critical security flaw resides within the application's handling of certain presentation elements and can be exploited through social engineering techniques where attackers deliver malicious files via email attachments, download links, or compromised websites. The vulnerability specifically manifests when PowerPoint processes malformed slide data structures that exceed allocated memory boundaries in the heap memory region, creating a condition where adjacent memory blocks become overwritten with attacker-controlled data.
The technical implementation of this vulnerability involves improper bounds checking during the parsing of presentation objects such as shapes, animations, or embedded media elements within pptx files. When PowerPoint encounters oversized or malformed data structures, it fails to validate input parameters properly before copying data into fixed-size heap buffers, allowing an attacker to overwrite critical memory locations including return addresses, function pointers, or other control structures necessary for normal program execution. This memory corruption directly enables arbitrary code execution with the privileges of the targeted user account, making it particularly dangerous in enterprise environments where users often run applications with elevated permissions.
The operational impact of this vulnerability extends beyond simple local privilege escalation as it provides attackers with persistent access to target systems and facilitates further lateral movement within networks. Once successfully exploited, the attacker can establish backdoors, exfiltrate sensitive data, deploy additional malware payloads, or use the compromised system as a launch point for attacking other network resources. The vulnerability affects multiple versions of Microsoft Office PowerPoint across different operating systems including windows 7 through windows 10 and office 2016 through office 2019, making it particularly widespread in corporate environments where these applications remain commonly deployed.
Security professionals should implement immediate mitigations including applying the latest microsoft security patches, enabling exploit protection mechanisms such as data execution prevention and address space layout randomization, and configuring email filters to block suspicious attachments. Additionally, organizations should deploy network monitoring solutions to detect potential exploitation attempts and establish user awareness training programs to reduce successful social engineering attacks. The vulnerability aligns with CWE-121 heap-based buffer overflow classification and represents a common technique used in the ATT&CK framework under initial access and execution phases where adversaries leverage software vulnerabilities to gain system access. Organizations must also consider implementing application whitelisting policies to restrict execution of untrusted office files and maintain comprehensive incident response procedures to address potential exploitation attempts.