CVE-2026-68805 in Office
Summary
by MITRE • 08/12/2026
Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 08/12/2026
A heap-based buffer overflow vulnerability exists in Microsoft Office Excel that enables remote code execution when a maliciously crafted file is opened by an unsuspecting user. This vulnerability resides in the way Excel processes certain data structures within spreadsheet files, specifically when handling malformed or oversized arrays during memory allocation operations. The flaw occurs when Excel attempts to allocate memory on the heap for processing user-supplied data without proper bounds checking, allowing an attacker to overwrite adjacent memory locations with malicious code. The vulnerability is classified under CWE-121 Heap-based Buffer Overflow, which represents a critical weakness in memory management where insufficient validation of buffer boundaries allows attackers to corrupt program execution flow.
The technical exploitation of this vulnerability requires an attacker to craft a specially formatted Excel file containing malicious data structures that trigger the buffer overflow condition when processed by the vulnerable application. When a user opens such a file, the heap corruption can lead to arbitrary code execution with the privileges of the victim user. This type of attack falls under the ATT&CK technique T1059 Command and Scripting Interpreter where attackers leverage legitimate system processes to execute malicious payloads. The vulnerability is particularly dangerous because it can be delivered through various attack vectors including email attachments, malicious websites, or compromised documents shared via collaboration platforms.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with persistent access to target systems and enables further exploitation within network environments. Once successfully exploited, the attacker gains a foothold that can be used for data exfiltration, lateral movement, or installation of additional malware. Organizations running affected versions of Microsoft Office Excel are at significant risk since the attack requires minimal user interaction beyond opening a malicious file, making it particularly effective in social engineering campaigns. The vulnerability affects multiple versions of Microsoft Office and requires immediate patching to prevent exploitation, as no reliable workarounds exist for this type of memory corruption issue.
Mitigation strategies should focus on implementing comprehensive security controls including regular patch management, application whitelisting, email filtering, and user education programs to recognize potentially malicious attachments. Network segmentation and monitoring for suspicious file access patterns can help detect exploitation attempts. Microsoft has released security updates that address this vulnerability through improved memory management routines and enhanced input validation in Excel's parsing engine. Organizations should also implement automated threat hunting processes to identify potential exploitation attempts using behavioral indicators associated with heap overflow attacks, as these vulnerabilities often produce distinctive patterns of memory corruption that can be detected by advanced endpoint protection systems.