CVE-2026-88175 in Office
Summary
by MITRE • 10/14/2026
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described constitutes a critical security flaw within the Microsoft Office Excel application, specifically categorized as an out-of-bounds read condition. This type of memory corruption error occurs when software attempts to access data at a memory location that lies outside the intended buffer boundaries. In the context of Excel, this typically manifests during the parsing or rendering of complex spreadsheet files containing specially crafted elements such as formulas, embedded objects, or specific formatting structures. When an attacker crafts a malicious document designed to exploit this flaw, they can trigger the application to read from memory addresses that do not belong to the allocated buffer for that operation. This deviation from standard memory access protocols allows the program to retrieve sensitive data stored in adjacent memory regions, which may contain credentials, session tokens, or other confidential information belonging to the user or the system hosting the Office suite.
From a technical perspective, this vulnerability aligns with Common Weakness Enumeration identifier CWE-125, which defines out-of-bounds read errors. These flaws are particularly dangerous because they do not necessarily cause an immediate application crash, unlike buffer overflows that lead to code execution. Instead, they facilitate information disclosure by leaking memory contents back to the attacker through the malformed input data structure. The exploitability of this flaw relies heavily on social engineering or automated distribution mechanisms where a victim is induced to open a malicious file via email, network shares, or web downloads. Once opened, Excel processes the content and inadvertently exposes internal memory states that were not intended for public access, thereby compromising the confidentiality integrity of the environment in which it operates.
The operational impact of this vulnerability extends beyond simple data leakage. By disclosing sensitive information over a network, an attacker can gather intelligence about the target organization's infrastructure, user identities, or active sessions. This initial foothold can serve as a precursor to more severe attacks such as privilege escalation or lateral movement within a corporate network. The ability to exfiltrate memory contents remotely makes this vulnerability particularly relevant in enterprise environments where Excel is ubiquitously used for data analysis and reporting. Attackers may leverage the leaked information to craft targeted phishing campaigns, bypass authentication mechanisms, or identify high-value targets based on the specific applications and services running on the compromised machine.
To mitigate the risks associated with this out-of-bounds read vulnerability, organizations must prioritize immediate patching of all affected Microsoft Office versions through official Windows Update channels. Security administrators should enforce strict email filtering policies to block attachments from untrusted sources and disable macro execution by default unless explicitly required for business operations. Additionally, implementing application control solutions can prevent the execution of unauthorized scripts or binaries that might be deployed following the initial exploitation. Users must be educated on recognizing suspicious file types and avoiding documents received from unknown entities. Regular vulnerability scanning and penetration testing should also be conducted to identify any unpatched instances within the network infrastructure, ensuring compliance with industry standards such as MITRE ATT&CK technique T1005 which covers data from local system memory extraction.