CVE-2026-97844 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 memory read operation. This type of error typically arises when the software fails to properly validate input data or array indices before accessing memory locations. In the context of DNS servers, which are fundamental components of internet connectivity responsible for resolving domain names to IP addresses, such a flaw can be triggered by processing specially crafted network packets. The core technical issue involves the application attempting to read from a memory address that lies outside the allocated buffer boundaries. While out-of-bounds reads generally do not allow direct code execution like their write counterparts, they are particularly dangerous because they enable the disclosure of sensitive information stored in adjacent memory regions. This can include internal server configurations, cryptographic keys, session tokens, or other private data structures that were previously loaded into memory for legitimate processing purposes.
From an operational perspective, this vulnerability allows an authorized attacker to exfiltrate confidential system information over a network connection. The term "authorized" implies that the attacker possesses valid credentials or access privileges within the DNS environment, which lowers the barrier for exploitation but does not diminish the severity of the data leakage. Once triggered, the malformed request causes the DNS server to return unexpected data from its memory space rather than the intended DNS response. This side-channel effect can be leveraged by attackers to map out internal network structures, identify running services, or steal authentication credentials that might be cached in memory. The impact is severe because it compromises the confidentiality of the system and potentially undermines trust in the integrity of the name resolution service provided by the organization.
In terms of industry standards classification, this vulnerability aligns with Common Weakness Enumeration (CWE) ID 125, which defines Out-of-bounds Read. This weakness category highlights scenarios where a read operation is performed with an index or pointer that exceeds the bounds of the intended buffer. Furthermore, from a tactical standpoint within the MITRE ATT&CK framework, this behavior corresponds to techniques related to Data Exfiltration over C2 Channels and potentially System Information Discovery. Attackers may use this flaw as part of a broader reconnaissance phase to gather intelligence about the target environment before proceeding to more intrusive actions such as privilege escalation or lateral movement. The ability to read arbitrary memory contents effectively turns the DNS server into an information leak vector, bypassing traditional access controls that might otherwise restrict direct file system access.
Mitigation strategies for this vulnerability must focus on both immediate remediation and long-term architectural improvements. The primary defense is the application of vendor-provided security patches or updates that address the specific memory management error in the DNS server software. Organizations should prioritize deploying these fixes to all affected systems, ensuring that version control mechanisms are strictly enforced to prevent regression to vulnerable states. Additionally, implementing strict input validation and bounds checking within custom configurations or extensions can help mitigate similar risks if the source code is accessible for modification. Network-level defenses such as Intrusion Detection Systems (IDS) should be configured to detect anomalous DNS query patterns indicative of memory exploitation attempts, although this may not catch all variants due to the complexity of crafting precise out-of-bounds triggers. Regular security audits and static application security testing (SAST) during development phases are also recommended to identify such buffer handling errors before deployment. Finally, limiting network access to DNS servers through firewalls and restricting administrative privileges can reduce the attack surface available to potential adversaries seeking to exploit this information disclosure flaw.