CVE-2026-62883 in Windows
Summary
by MITRE • 08/11/2026
Numeric truncation error in Windows DNS allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 08/12/2026
This vulnerability represents a numeric truncation error within the Windows Domain Name System implementation that enables local privilege escalation for authenticated attackers. The flaw occurs when the dns service processes certain numeric values during authentication or authorization sequences, where integer overflow or truncation conditions allow malicious input to be interpreted incorrectly. Such errors typically arise from improper validation of input parameters before arithmetic operations or memory allocation decisions are made within the dns server component.
The technical exploitation involves an authenticated user leveraging specific input patterns that cause numeric truncation during internal processing of dns requests or configuration updates. This creates a condition where legitimate authorization checks fail due to incorrect integer comparisons, potentially allowing unauthorized access to privileged dns operations or system resources. The vulnerability falls under the CWE-190 category for integer overflow and under CWE-20 for improper input validation, representing a classic case of insufficient boundary checking in cryptographic or authentication contexts.
From an operational perspective, this vulnerability impacts organizations running windows dns servers where local accounts have access to dns management interfaces. Attackers must first establish a valid account on the system, typically through legitimate administrative or user credentials before attempting privilege escalation. The attack vector requires local system access and specific knowledge of the dns service behavior to craft malicious input sequences that trigger the truncation condition.
The impact extends beyond simple privilege escalation as it may enable attackers to modify dns records, create unauthorized zones, or potentially disrupt critical network services. Organizations with centralized dns infrastructure face elevated risk as successful exploitation can lead to widespread network disruption or facilitate further attacks through dns poisoning or cache poisoning techniques. This vulnerability aligns with ATT&CK technique T1068 for local privilege escalation and potentially T1482 for domain trust relationships manipulation.
Mitigation strategies should focus on applying microsoft security updates promptly, implementing proper input validation controls within dns service configurations, and restricting local access to dns management interfaces. Network segmentation and principle of least privilege enforcement can limit the impact if exploitation occurs. Additionally, monitoring for unusual dns configuration changes or authentication patterns may help detect exploitation attempts. Organizations should also consider implementing additional authentication layers and regular security assessments of dns server configurations to identify similar numeric truncation vulnerabilities in other system components.