Description

Numeric truncation error in Windows DNS allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.7",
  "pubDate": "2026-08-11T17:18:39.010Z",
  "pubdate": "2026-08-11T17:18:39.010Z",
  "executiveSummary": "A numeric truncation error vulnerability exists within Windows DNS, potentially allowing an authorized local attacker to elevate privileges.\nThe vulnerability affects Windows DNS components, enabling a local user to manipulate data handling mechanisms and execute arbitrary actions with elevated privileges.\nSuccessful exploitation of this flaw requires local access and specific authorization on the target system, granting the adversary the capability to compromise system integrity and confidentiality.\nThe primary risk implication is local privilege escalation, which can lead to a complete compromise of the affected host if chained with other vulnerabilities or misconfigurations.\nRisk mitigation requires applying official vendor patches or updates as soon as they become available, alongside enforcing strict least-privilege principles for local user accounts to limit potential damage from unauthorized access.",
  "technicalDetails": "The vulnerability stems from a numeric truncation error within the data processing routines of Windows DNS.\nRoot cause analysis indicates that improper handling of integer boundaries during size calculations or data parsing operations leads to memory corruption or logic flaws.\nWhen specific numeric inputs are processed by the vulnerable component, the truncation causes a mismatch between allocated buffer sizes and the actual amount of data written or read.\nAn authorized local attacker can exploit this weakness by supplying specially crafted inputs to the Windows DNS service or associated local interfaces, triggering the numeric truncation condition.\nThe attack flow begins with the authenticated local user initiating a targeted interaction with the vulnerable Windows DNS component.\nUpon receiving the malformed input, the application fails to safely handle the truncated numeric value, resulting in improper memory manipulation or insecure state transitions.\nThis behavior allows the payload or execution flow to bypass standard access controls, culminating in an elevation of privileges to a higher security context on the local machine.\nPrerequisites for exploitation include local interactive or programmatic access to the host system and valid authorization to interact with the vulnerable component.\nThe network exposure for this specific vector is limited to local attack surfaces, meaning remote exploitation over the network is not directly facilitated by this flaw alone.\nPost-exploitation impact includes the potential execution of unauthorized commands or code within the context of a privileged service account, facilitating further system enumeration, credential theft, or lateral movement within the environment."
}