CVE-2026-97011 in Office
Summary
by MITRE • 10/14/2026
Use of uninitialized resource in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described involves the improper initialization of resources within Microsoft Office Excel, specifically creating conditions that allow for remote code execution when processing maliciously crafted files or data streams. This class of flaw typically stems from memory management errors where the application allocates memory but fails to properly initialize it before use, leaving residual data from previous operations in those memory locations. When an attacker constructs a specially designed file containing specific sequences of bytes that trigger this uninitialized state during parsing or rendering processes, they can manipulate how Excel interprets and executes instructions within its internal structures. The core technical flaw lies in the failure to zero out or explicitly set initial values for allocated buffers or object properties before they are accessed by subsequent logic paths. This oversight allows an attacker to control critical execution flow parameters such as function pointers, return addresses, or virtual table indices embedded within these uninitialized regions. By carefully crafting input data that exploits this lack of initialization, the attacker can achieve arbitrary code execution on the victim's system with the privileges of the currently logged-in user.
From a technical perspective, this vulnerability aligns closely with CWE-908, which denotes the use of uninitialized resource, and often overlaps with CWE-125, out-of-bounds read, or CWE-787, out-of-bounds write, depending on how the uninitialized data is utilized to corrupt memory structures. The operational impact is severe because it enables a network-based attack vector where no user interaction beyond opening the malicious file is strictly required in many scenarios, although social engineering often plays a role in convincing users to open attachments or visit compromised websites hosting exploit kits. Attackers can leverage this flaw to install malware, steal sensitive information, establish persistent backdoors, or pivot further into internal networks. The ability to execute code remotely makes this particularly dangerous as it bypasses traditional perimeter defenses that might block direct network connections but fail to inspect the content of office documents for embedded exploits.
Mitigation strategies primarily focus on applying vendor-supplied security patches and updates promptly to ensure that memory management routines are corrected and uninitialized resources are properly initialized before use. Organizations should enforce strict email filtering policies to scan attachments for known exploit signatures and restrict macro execution unless explicitly trusted by users. Additionally, enabling data execution prevention (DEP) and address space layout randomization (ASLR) can mitigate the success rate of exploitation attempts by making it harder for attackers to reliably predict memory layouts or execute shellcode in non-executable memory regions. User awareness training is also critical to prevent social engineering tactics that lead to opening untrusted files. From a defensive monitoring standpoint, security operations centers should look for anomalies such as Excel spawning unexpected child processes like cmd.exe or powershell.exe, which are common indicators of successful exploitation according to MITRE ATT&CK techniques related to command and script interpreter abuse and process injection. Regular vulnerability scanning and patch management cycles remain the most effective defense against this type of memory corruption flaw in widely deployed productivity software.