CVE-2026-97820 in Windows
Summary
by MITRE • 10/14/2026
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 • 10/14/2026
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 safety error occurs when the software attempts to access data at a memory location that is outside the boundaries of the intended buffer or array. In the context of DNS servers, which are fundamental components of internet infrastructure 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, leading to unauthorized disclosure of sensitive data stored in adjacent memory regions that were not intended to be accessed by the DNS processing logic.
From a technical perspective, out-of-bounds reads are often categorized under CWE-125, which defines Out-of-Bounds Read as accessing memory beyond the end or before the beginning of an allocated buffer. This flaw typically arises due to insufficient validation of input parameters or incorrect calculation of array indices during packet parsing or response generation processes within the DNS server software. When a specially crafted DNS query is processed by the vulnerable component, the application may read data from adjacent memory locations that contain sensitive information such as internal network configurations, cached records, authentication tokens, or other proprietary data structures. The lack of proper bounds checking allows these extraneous bytes to be included in the response sent back to the client, effectively leaking information that should remain isolated within the server's secure execution environment.
The operational impact of this vulnerability is significant, particularly because it requires authorized access for exploitation. While this requirement might seem like a mitigating factor, it does not eliminate the risk entirely. Authorized attackers could include compromised service accounts, insider threats with legitimate credentials, or external actors who have successfully breached perimeter defenses and obtained valid authentication tokens. Once such an attacker exploits the out-of-bounds read, they can extract sensitive information that aids in further reconnaissance activities within the network. This disclosed data may reveal internal IP addresses, server roles, software versions, or other architectural details that facilitate more sophisticated attacks against critical infrastructure components. The ability to disclose this information over a network means that the attacker does not need physical access to the machine, allowing for remote exploitation and potential lateral movement across the enterprise network.
In terms of threat modeling, this vulnerability aligns with ATT&CK technique T1005, which refers to Data from Local System, specifically under sub-techniques related to application data or system configuration files depending on what specific memory regions are exposed. The attack vector is classified as Network (T1078) combined with the exploitation of a software flaw that leads to information leakage. Defense-in-depth strategies must be employed to mitigate this risk. Immediate remediation involves applying vendor-provided patches that address the buffer boundary checks within the DNS server software. Additionally, organizations should implement strict access controls and principle of least privilege to limit who can interact with the DNS service, reducing the attack surface for authorized users. Network segmentation and monitoring solutions such as Intrusion Detection Systems (IDS) configured to detect anomalous DNS traffic patterns or unusual data exfiltration attempts can also help in identifying potential exploitation activities before significant damage occurs. Regular security audits and static code analysis during software development lifecycles are essential preventive measures to identify and rectify memory safety issues like out-of-bounds reads before they reach production environments.