CVE-2026-97823 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 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 connectivity and often handle high volumes of sensitive query traffic, such flaws can have severe implications for system integrity and 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 information across the network.
From a technical perspective, out-of-bounds reads typically arise due to insufficient validation of input parameters or incorrect calculation of buffer sizes during packet processing. When a DNS server processes a query, it allocates specific amounts of memory for storing response data and intermediate variables. If the logic governing these allocations fails to properly verify that incoming data does not exceed expected limits, the application may read from adjacent memory regions. These adjacent regions often contain sensitive information such as internal network configurations, cached records, authentication tokens, or even parts of other users' queries. The exploitation of this flaw relies on precise control over input data to trigger the erroneous memory access pattern, allowing the attacker to extract contents that were not intended for public consumption.
The operational impact of this vulnerability is significant, particularly because it requires authorized access. While this requirement might seem like a mitigating factor, in many enterprise environments, compromised credentials or insider threats can easily bridge this gap. Once exploited, the disclosure of information can facilitate further attacks such as lateral movement within the network, privilege escalation, or targeted phishing campaigns based on harvested data. The ability to read arbitrary memory contents undermines the confidentiality guarantees provided by the DNS service and can lead to regulatory compliance violations depending on the nature of the disclosed data. Furthermore, since DNS is a ubiquitous service, successful exploitation could potentially impact multiple systems if the vulnerability exists in shared infrastructure components or recursive resolvers used across an organization.
This flaw aligns with Common Weakness Enumeration (CWE) category CWE-125, which defines out-of-bounds read vulnerabilities where software reads data past the end of a buffer or array. In terms of offensive security frameworks, this vulnerability supports techniques associated with ATT&CK tactic TA0043, specifically Reconnaissance activities such as Data from Network Shared Drives (T1175) or potentially System Information Discovery if internal network details are exposed. The exploitation vector is classified under remote attack vectors but requires authentication, placing it in a nuanced category of authenticated remote code execution precursors that lead to information disclosure rather than direct system compromise.
Mitigation strategies for this vulnerability must focus on both immediate remediation and long-term architectural improvements. Organizations should immediately apply vendor-provided patches or updates that address the specific memory handling logic within the DNS server software. It is crucial to verify that all instances of the affected service are updated, including secondary servers and any clustered environments where configuration drift might leave some nodes vulnerable. Beyond patching, implementing strict input validation mechanisms at the application layer can prevent malformed packets from triggering the out-of-bounds condition. Network segmentation should be enforced to limit the exposure of DNS servers to only necessary authorized clients, reducing the attack surface available to potential intruders who have obtained valid credentials.
Additionally, deploying intrusion detection systems and network monitoring tools configured to detect anomalous DNS query patterns can help identify attempted exploitation in real-time. Regular security audits focusing on memory safety issues are recommended for critical infrastructure components. Developers responsible for maintaining or customizing DNS server software should adopt secure coding practices that emphasize bounds checking and the use of safe string handling libraries. By combining timely patching with robust network controls and proactive monitoring, organizations can effectively mitigate the risks associated with this out-of-bounds read vulnerability and maintain the integrity of their domain name resolution services.