CVE-2026-97775 in Office
Summary
by MITRE • 10/15/2026
Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/15/2026
The vulnerability described involves a use-after-free condition within the Microsoft Office Excel application, which presents a critical security risk allowing for remote code execution via network-based attacks. This class of memory corruption flaw occurs when software continues to use a pointer after it has been freed from dynamic memory allocation. In the context of Excel, this typically manifests through the parsing and rendering of complex document structures or embedded objects where internal data structures are deallocated prematurely while references to those same memory regions remain active within the application's runtime environment. An attacker can craft a malicious file containing specially designed content that exploits this timing discrepancy in memory management operations. When an unsuspecting user opens such a file, whether through direct download, email attachment, or network share access, Excel processes the malformed data and triggers the use-after-free condition during its internal handling routines.
The operational impact of this vulnerability is severe due to the potential for arbitrary code execution with the privileges of the current user. Because Microsoft Office applications often run with elevated permissions relative to standard system operations, successful exploitation can allow an attacker to install programs, view, change, or delete data, or create new accounts with full user rights. The network vector implies that this vulnerability is particularly dangerous in enterprise environments where documents are frequently shared across organizational boundaries without sufficient scrutiny of their contents. Attackers may leverage social engineering tactics combined with the technical exploit to trick users into opening malicious spreadsheets, thereby gaining a foothold within the internal network infrastructure. This can serve as an initial access vector for more advanced persistent threats or ransomware deployments that rely on lateral movement and privilege escalation following initial compromise.
From a standards perspective, this vulnerability aligns closely with CWE-416, which defines use-after-free errors where references to memory are used after they have been freed. The exploitation technique falls under the MITRE ATT&CK framework category of Initial Access, specifically within techniques involving malicious files or links designed to execute code on target systems. It also relates to Defense Evasion tactics if the attacker employs obfuscation methods to bypass security controls that inspect file contents before execution. Understanding these mappings helps in categorizing the threat landscape and aligning remediation efforts with established industry best practices for memory safety and application hardening.
Mitigation strategies must focus on both immediate patching and long-term architectural improvements. Organizations should prioritize deploying the latest Microsoft Office updates and security patches that address this specific use-after-free flaw, as vendors typically release hotfixes to correct such critical vulnerabilities in their software supply chain. Additionally, implementing strict email filtering policies that scan attachments for known malicious patterns can reduce the attack surface by preventing infected files from reaching end-user devices. User awareness training is equally important, emphasizing caution when opening documents received from untrusted sources or unexpected senders. On a technical level, enabling macro security settings to disable all macros without notification and utilizing application whitelisting tools can further restrict the ability of exploited code to execute arbitrary commands on the host system.