CVE-2026-97842 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 routing and resolution, such flaws can have severe implications for system stability and information confidentiality. The specific nature of this vulnerability allows an attacker who has already established authorized access to exploit the improper memory handling mechanism. This authorization requirement suggests that the attack vector is not remote or unauthenticated but rather requires a foothold within the network segment where the DNS server resides, potentially through compromised credentials, insider threats, or lateral movement from another breached system.
From a technical perspective, an out-of-bounds read typically arises when input validation fails to correctly verify the length of data being processed against the allocated buffer size. When the DNS server processes specific queries or malformed packets that trigger this condition, it reads memory contents adjacent to the intended target area. This adjacent memory may contain sensitive operational data, such as internal network configurations, cached DNS records containing user query histories, cryptographic keys used for zone transfers, or other process-specific information. The disclosure of this information can provide an attacker with valuable intelligence about the internal architecture of the organization, facilitating further attacks such as privilege escalation, targeted phishing based on known employee domains, or bypassing security controls that rely on network topology knowledge.
The operational impact of this vulnerability extends beyond mere data leakage. While the primary consequence is the unauthorized disclosure of information, the instability caused by memory access violations can also lead to service degradation if the server attempts to recover from the error in an unpredictable manner. Although out-of-bounds reads are less likely than out-of-bounds writes to cause immediate code execution or system crashes, they remain a significant risk because they violate the principle of least privilege and confidentiality. For organizations relying on DNS for critical business operations, any compromise that reveals internal network details undermines trust in the infrastructure's integrity. Furthermore, if the disclosed information includes sensitive identifiers or private data, it may also trigger compliance violations under regulations such as GDPR, HIPAA, or PCI-DSS, depending on the nature of the exposed data and the industry sector involved.
In terms of classification standards, this vulnerability aligns with CWE-125, which defines out-of-bounds read errors where a program reads memory beyond the end of an array or buffer. It also relates to CWE-200, Exposure of Sensitive Information to an Unauthorized Actor, as the ultimate result is the leakage of data that should remain confidential. From a tactical perspective within the MITRE ATT&CK framework, this vulnerability supports techniques associated with Discovery and Collection phases, such as T1087 (Account Discovery) or T1530 (Data from Cloud Storage), if the DNS server holds cached records of cloud service interactions. The requirement for authorization places it in a context where an attacker has already bypassed initial perimeter defenses, highlighting the importance of defense-in-depth strategies and strict access controls even within trusted network zones.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. The most effective solution is to apply vendor-provided patches or updates that correct the memory handling logic in the DNS server software. Organizations should prioritize deploying these fixes on all affected systems, particularly those exposed to internal networks where lateral movement might occur. In addition to patching, implementing strict network segmentation can limit the scope of potential exploitation by isolating DNS servers from general user workstations and other critical assets. Access control lists (ACLs) should be reviewed to ensure that only necessary services and administrators have access to the DNS server interfaces. Furthermore, deploying intrusion detection systems with signatures for malformed DNS packets can help identify attempts to exploit this vulnerability in real-time. Regular security audits and code reviews focusing on memory safety are also recommended to prevent similar issues from arising in future software versions or custom configurations.