CVE-2026-55125 in Office
Summary
by MITRE • 07/14/2026
Heap-based buffer overflow in Microsoft Office 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 within Microsoft Office applications that enables unauthorized attackers to execute arbitrary code on a target system with local privileges. This critical security flaw resides in the memory management handling of certain Office components when processing specially crafted malicious files or content. The vulnerability stems from insufficient bounds checking during heap allocation operations where attacker-controlled data can overwrite adjacent memory regions beyond the intended buffer boundaries. When Microsoft Office processes vulnerable input, the heap corruption can lead to arbitrary code execution within the context of the currently logged-on user. This type of vulnerability falls under CWE-121 Heap-based Buffer Overflow which is classified as a serious memory safety issue that directly impacts application stability and security. The attack typically requires social engineering to convince users to open malicious Office documents containing crafted payloads designed to trigger the buffer overflow condition during document rendering or processing operations.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with persistent access to target systems through local privilege escalation opportunities. Once successfully exploited, adversaries can leverage the compromised Office application to establish footholds for further lateral movement within network environments. The vulnerability affects multiple Microsoft Office products including Word, Excel, and PowerPoint applications across various Windows operating system versions. Attackers often employ techniques such as return-oriented programming or function pointer overwrites to achieve reliable code execution, making this vector particularly dangerous for enterprise environments where Office applications are frequently used. The exploitability of heap-based buffer overflows is enhanced when users have elevated privileges within the Office application context, potentially allowing attackers to gain system-level access and execute malicious payloads with full administrative rights.
Mitigation strategies should focus on immediate patch management and operational security controls to prevent exploitation of this vulnerability. Microsoft releases regular security updates through their monthly security bulletins that address such heap-based buffer overflow conditions, making timely patch deployment critical for maintaining system integrity. Organizations should implement application whitelisting policies that restrict execution of unsigned Office macros and limit user privileges when opening document attachments from untrusted sources. Network segmentation and endpoint detection solutions can help identify potential exploitation attempts through anomalous memory access patterns or unusual process behavior associated with heap corruption attacks. Security teams should also consider deploying exploit protection mechanisms such as address space layout randomization and data execution prevention features to make successful exploitation more difficult. The vulnerability demonstrates the importance of following secure coding practices including proper input validation, bounds checking, and memory management procedures that align with industry standards like those outlined in the software security development lifecycle framework. Additionally, organizations should maintain comprehensive incident response procedures specifically designed to handle heap-based buffer overflow exploitation attempts as these attacks often represent sophisticated multi-stage attack vectors requiring coordinated defensive measures across multiple security domains.