CVE-2026-97835 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 categorized 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 structure. In the context of DNS servers, which are fundamental components of internet routing and resolution services, 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 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 properly check the length of incoming data against the allocated buffer size before processing it. When a maliciously crafted packet or query is processed by the DNS server, the application may attempt to copy or reference memory addresses that do not belong to the current context. While out-of-bounds reads are often less immediately catastrophic than out-of-bounds writes because they typically result in information disclosure rather than arbitrary code execution, they remain highly dangerous. The attacker can leverage this flaw to read sensitive data from adjacent memory locations, which may contain stack frames, heap metadata, or other process-specific information. This capability directly facilitates the leakage of internal network topology details, cached DNS records containing private domain names and IP addresses, or potentially cryptographic keys if they reside in accessible memory regions.
The operational impact of this vulnerability is significant for organizations relying on their DNS infrastructure for secure communications and service availability. By disclosing sensitive information over a network, an attacker can perform reconnaissance activities that aid further exploitation attempts. For instance, knowledge of internal hostnames, IP address ranges, or specific software versions cached by the server can be used to craft more targeted attacks against other systems within the enterprise perimeter. Furthermore, if the disclosed data includes session tokens or authentication cookies stored in memory, it could lead to account takeover and unauthorized access to critical applications. The presence of such a vulnerability undermines the integrity and confidentiality pillars of the CIA triad, eroding trust in the DNS service's ability to provide reliable and secure name resolution services.
In terms of industry standards classification, this flaw aligns with CWE-125: Out-of-bounds Read, which defines the scenario where software reads data past the end or before the beginning of a buffer. Additionally, from an offensive security perspective as defined by MITRE ATT&CK, this activity falls under techniques related to Data from Local System Retrieval and potentially Credential Access if sensitive authentication material is exposed. The attack vector corresponds to T1078: Valid Accounts, given that authorization is required, indicating the attacker must possess legitimate credentials or have compromised an account with sufficient privileges to interact with the DNS service API or interface.
Mitigation strategies for this vulnerability should focus on both immediate remediation and long-term architectural improvements. The primary action is to apply vendor-provided patches or updates that address the specific memory handling error in the DNS server software. Organizations must ensure their patch management processes are agile enough to deploy these fixes promptly, especially since authorized attackers may already be present within the network environment. Beyond patching, implementing strict input validation and bounds checking mechanisms during development is crucial for preventing similar issues in future versions of the software. Network segmentation should also be reviewed to limit the exposure of DNS servers; ensuring that only necessary services can communicate with the DNS infrastructure reduces the attack surface available to potential intruders who have gained initial access through other means.
Security monitoring and detection capabilities must be enhanced to identify attempts to exploit this vulnerability or signs of information leakage resulting from it. Log analysis should focus on unusual query patterns, excessive memory usage spikes within the DNS process, or error messages related to buffer overflows that might indicate exploitation activity. Deploying intrusion detection systems with signatures for known exploits targeting out-of-bounds reads in DNS services can provide an additional layer of defense. Furthermore, adopting a zero-trust architecture model ensures that even if an attacker gains authorized access, their ability to move laterally and exploit memory vulnerabilities is constrained by strict identity verification and least-privilege principles applied across all network segments. Regular security assessments, including static application security testing and dynamic analysis during the software development lifecycle, are essential to identify and rectify such memory safety issues before they can be exploited in production environments.