Description

Heap-based buffer overflow in Windows DNS allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.7",
  "pubDate": "2026-08-11T17:19:07.787Z",
  "pubdate": "2026-08-11T17:19:07.787Z",
  "executiveSummary": "This vulnerability is classified as a heap-based buffer overflow affecting the Windows DNS service. The flaw enables an authenticated local attacker to execute arbitrary code within the context of a privileged account, resulting in local elevation of privileges on targeted systems.\nThe security implication of this vulnerability is severe, as successful exploitation compromises the integrity and confidentiality of the host operating system by allowing low-privileged actors to escalate their access levels. The risk profile is heightened in enterprise environments where Windows DNS is deployed across numerous servers and workstations.\nExploitation requires the attacker to possess prior local access to the target system and appropriate authorization to interact with the vulnerable Windows DNS component. The threat actor must craft specialized input designed to corrupt heap memory structures managed by the affected service, thereby achieving arbitrary code execution through memory manipulation.",
  "technicalDetails": "The vulnerability resides within the heap memory management routines of the Windows DNS service. Specifically, improper bounds checking during the processing of dynamic memory allocations leads to a heap-based buffer overflow condition. The vulnerable component fails to adequately validate the size of incoming data relative to the allocated buffer size on the heap.\nExploitation occurs when an authorized local attacker interacts with the Windows DNS service and submits specially crafted data designed to exceed the boundaries of the designated heap buffer. As the input is processed, excess data overflows the heap chunk, overwriting adjacent memory structures, function pointers, or critical application metadata.\nThe attack flow proceeds as follows: First, the attacker establishes local access and authenticates to the system. Second, the attacker formulates a malicious payload intended to trigger the parsing routines of the vulnerable Windows DNS component. Third, the crafted input is delivered to the service, initiating an unsafe memory copy operation. Fourth, the overflow corrupts adjacent heap memory, allowing the attacker to redirect execution flow.\nBy hijacking the control flow, the payload executes malicious instructions with the elevated privileges associated with the Windows DNS service process. This post-exploitation state grants the attacker extensive control over the underlying operating system, facilitating further compromise, credential harvesting, or lateral movement within the network domain.\nThe attack vector is strictly local, requiring the attacker to already possess execution rights on the host system and the necessary permissions to interact with the Windows DNS service. No specific network exposure or remote attack vector is mandated for this local elevation of privilege vulnerability."
}