CVE-2026-65799 in Windows
Summary
by MITRE • 08/12/2026
Integer overflow or wraparound 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 critical integer overflow condition within the windows dns service that enables local privilege escalation for authenticated attackers. The flaw occurs when the dns server processes certain input parameters that trigger arithmetic operations resulting in integer wraparound behavior. When an attacker with valid credentials executes malicious requests against the dns service, the overflow can cause memory corruption that potentially allows arbitrary code execution with elevated privileges.
The technical implementation of this vulnerability stems from inadequate input validation within the dns server component where integer calculations fail to properly check for overflow conditions before performing arithmetic operations. This type of flaw falls under the common weakness enumeration category CWE-190 which specifically addresses integer overflow conditions. The vulnerability exists in the dns server's handling of resource record updates or query processing where numeric values are manipulated without proper boundary checking mechanisms.
From an operational perspective this vulnerability presents significant risk to organizations as it requires only authenticated access to exploit, meaning that any user with valid credentials can potentially leverage this flaw. Attackers typically need to establish a foothold through legitimate means such as employee accounts or compromised credentials before attempting privilege escalation. The impact extends beyond simple local privilege escalation as the elevated privileges could enable attackers to modify dns records, create malicious entries, or potentially pivot to other systems within the network infrastructure that relies on dns services for communication.
The attack vector typically involves sending specially crafted dns requests that trigger the integer overflow condition during processing. These requests may include malformed resource record data or excessive parameters that cause the arithmetic operations to exceed maximum integer values and wrap around to negative or unexpected values. The vulnerability affects various windows server versions including but not limited to windows server 2012 through windows server 2019, making it particularly concerning for enterprise environments where dns infrastructure is critical to network operations.
Mitigation strategies must include immediate deployment of microsoft security patches addressing the specific integer overflow conditions within dns services. Organizations should also implement network segmentation and access controls to limit exposure of dns servers to untrusted networks. Additionally monitoring solutions should be configured to detect unusual dns query patterns or resource record modifications that could indicate exploitation attempts. The defense in depth approach should include regular vulnerability assessments and penetration testing focusing on dns server configurations. Implementing principle of least privilege for dns service accounts and maintaining comprehensive audit logging will help detect unauthorized access attempts. This vulnerability aligns with attack techniques documented under the mitre att&ck framework within the privilege escalation category where attackers seek to gain higher level permissions through system weaknesses.