CVE-2026-97836 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 memory read operation. This type of error occurs when software attempts to access data at a memory location that is outside the boundaries of its allocated 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 a flaw can be triggered by processing specially crafted network packets. The presence of this vulnerability indicates a failure in input validation and bounds checking mechanisms within the server's parsing logic, allowing an attacker to exploit memory access violations that typically result in information disclosure rather than immediate code execution or denial of service.
From a technical perspective, out-of-bounds reads are particularly dangerous because they allow unauthorized reading of adjacent memory contents without necessarily crashing the application immediately. When an authorized attacker sends maliciously constructed DNS queries to the vulnerable server, the processing routine may read beyond the intended buffer limits into neighboring memory regions. This can lead to the leakage of sensitive internal data structures, such as stack frames, heap metadata, or other process-specific information that resides in close proximity to the targeted buffer. The disclosure of this information provides the attacker with valuable intelligence about the server's environment, potentially revealing version numbers, configuration details, or cryptographic keys stored in memory, which can facilitate further exploitation attempts against the system or its network peers.
The operational impact of this vulnerability is significant due to the privileged nature of DNS services and their exposure to external networks. Although the prompt specifies that an authorized attacker is required, meaning authentication credentials are necessary, the ability to disclose internal information over a network undermines the confidentiality integrity of the service. In many enterprise environments, access controls may be bypassed or compromised through other vectors such as credential theft or insider threats. Once an attacker gains authorization and exploits this out-of-bounds read, they can gather reconnaissance data that aids in lateral movement within the network. This aligns with the ATT&CK technique of T1082, System Information Discovery, where adversaries collect information about the target environment to plan subsequent attacks. The vulnerability also maps closely to CWE-125, Out-of-bounds Read, which is a common class of memory safety issues that persist in complex software systems despite decades of security awareness.
Mitigation strategies for this vulnerability must prioritize both immediate patching and long-term architectural improvements. Organizations should immediately apply the latest vendor-supplied patches or updates to the DNS server software, as these typically include fixes for buffer validation logic. In environments where patching is not immediately feasible, network segmentation can help limit exposure by restricting access to the DNS servers only from trusted subnets or specific application tiers that require name resolution services. Additionally, implementing strict input filtering and deep packet inspection at the perimeter firewall may help detect and block malformed packets that attempt to trigger out-of-bounds reads before they reach the vulnerable service component. Long-term remediation involves adopting memory-safe programming languages for critical network services and enforcing rigorous code review processes focused on bounds checking and secure coding standards such as those outlined in CWE-120, which addresses buffer copy operations without proper size checks. Regular vulnerability scanning and penetration testing should also be conducted to identify similar weaknesses before they can be exploited by malicious actors seeking to compromise organizational infrastructure.