CVE-2026-50408 in Office
Summary
by MITRE • 07/14/2026
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical out-of-bounds read flaw within Microsoft Office Excel that enables unauthorized attackers to potentially access sensitive local information through crafted malicious files or documents. The technical nature of this vulnerability stems from improper input validation and memory handling within the spreadsheet application's parsing mechanisms, where Excel fails to properly bounds-check array accesses when processing specially constructed data structures. Such flaws typically occur when the application reads memory locations beyond allocated buffer boundaries without adequate safeguards, potentially exposing sensitive data from adjacent memory regions. The vulnerability is particularly concerning in enterprise environments where Excel documents are frequently shared and processed, as it could be exploited through social engineering attacks involving malicious spreadsheet files delivered via email or other attack vectors.
The operational impact of this vulnerability extends beyond simple information disclosure, as it could potentially enable attackers to extract sensitive data including user credentials, system configuration details, or corporate intellectual property stored in memory. Attackers can craft specific Excel files that trigger the out-of-bounds read condition when opened by vulnerable versions of Microsoft Office, leading to unintended data exposure from adjacent memory locations. This type of vulnerability aligns with CWE-129, which specifically addresses improper validation of length of input buffers, and represents a variant of the broader category of buffer over-read conditions that have historically led to information disclosure attacks. The attack surface is significant given Excel's widespread use across organizations and its ability to process complex data structures including formulas, charts, and embedded objects.
Mitigation strategies for this vulnerability should include immediate deployment of Microsoft security patches and updates, which typically address the underlying memory handling issues through proper bounds checking and input validation mechanisms. Organizations should implement comprehensive email filtering and sandboxing solutions to prevent potentially malicious Excel files from reaching end users, while also maintaining up-to-date antivirus signatures that can detect known exploit patterns. Security awareness training for employees remains crucial to prevent successful social engineering attacks that might deliver these malicious documents. Additionally, network monitoring solutions should be configured to detect unusual file access patterns or attempts to read memory regions that could indicate exploitation attempts. The vulnerability demonstrates the importance of following secure coding practices such as those recommended in the OWASP Secure Coding Practices and aligns with ATT&CK technique T1059.005 for command and scripting interpreter, where attackers might leverage information disclosure to further their attack objectives through lateral movement or privilege escalation activities.