CVE-2026-97837 in Windows
Summary
by MITRE • 10/15/2026
Out-of-bounds read in DNS Server allows an authorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability described constitutes a critical security flaw within the Domain Name System (DNS) server infrastructure, specifically manifesting as an out-of-bounds read condition. This type of memory corruption error occurs when the software attempts to access data at a memory location that is outside the boundaries of the intended buffer or array structure. In the context of DNS servers, which are fundamental components of internet connectivity responsible for translating domain names into IP addresses, such flaws can have severe implications for system stability and information confidentiality. The specific nature of this vulnerability allows an attacker who has already gained authorized access to exploit the memory mismanagement issue to read sensitive data from adjacent memory locations that were not intended to be accessed by the application logic.
From a technical perspective, out-of-bounds reads are often categorized under CWE-125 in the Common Weakness Enumeration framework. This classification highlights issues where software reads past the end of an allocated buffer or array. In DNS servers, this can happen during the parsing and processing of incoming query packets or response structures. If the server fails to properly validate the length fields within these network messages before copying data into internal buffers, it may read memory contents that belong to other processes or contain sensitive operational data such as cryptographic keys, session tokens, or internal configuration details. The presence of this flaw indicates a deficiency in input validation and bounds checking routines within the DNS server software codebase.
The impact of exploiting an out-of-bounds read is primarily centered on information disclosure rather than immediate remote code execution, although it can serve as a stepping stone for more severe attacks. An authorized attacker who leverages this vulnerability can potentially extract arbitrary memory contents from the DNS server process. This disclosed information could include internal network topology details, cached DNS records containing sensitive domain names and associated IP addresses, or even parts of other applications running on the same host if they share memory space with the DNS service. Such data leakage aids adversaries in reconnaissance efforts, allowing them to map out the target environment more accurately and plan further intrusion activities with greater precision.
In terms of threat modeling, this vulnerability aligns with ATT&CK technique T1005, which refers to Data from Local System. The attacker utilizes local access privileges to gather information that can be used for subsequent phases of an attack campaign. While the initial requirement is authorized access, once obtained, the exploitation of this flaw significantly lowers the barrier for deeper penetration into the network infrastructure. It enables the adversary to bypass certain security controls by gaining insights into how internal systems are configured and what data they handle, thereby facilitating lateral movement or privilege escalation attempts that rely on specific knowledge of the environment.
Mitigation strategies must focus on both immediate remediation and long-term defensive improvements. The most effective solution is to apply vendor-provided patches or updates that address the underlying code defect responsible for the out-of-bounds read condition. Organizations should prioritize deploying these fixes across all DNS server instances in their infrastructure, particularly those exposed to internal networks where authorized attackers might operate. Additionally, implementing strict input validation mechanisms and employing memory-safe programming practices during software development can prevent similar vulnerabilities from being introduced in future versions.
Beyond patching, defense-in-depth measures are essential to mitigate the risk posed by such flaws. Network segmentation should be enforced to limit the ability of unauthorized or compromised entities to reach DNS servers directly. Access control lists must be rigorously maintained to ensure that only legitimate users and systems can interact with critical infrastructure components like DNS services. Furthermore, deploying intrusion detection systems configured to monitor for anomalous memory access patterns or unusual query behaviors associated with exploitation attempts can provide early warning indicators of active attacks leveraging this vulnerability type. Regular security audits and code reviews focusing on buffer handling logic are also recommended to identify and rectify potential weaknesses before they can be exploited in production environments.