CVE-2026-62720 in Windows
Summary
by MITRE • 08/11/2026
Integer underflow (wrap or wraparound) in Windows DHCP Server allows an unauthorized attacker to disclose information over an adjacent network.
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Analysis
by VulDB Data Team • 08/11/2026
An integer underflow vulnerability exists in the windows dhcp server implementation that occurs when a malicious actor exploits improper handling of numeric values during network communication processes. This specific weakness manifests as a wraparound condition where arithmetic operations involving integer variables result in values that exceed the maximum representable range, causing the system to interpret the results incorrectly. The vulnerability specifically affects the dhcp server functionality within windows operating systems and creates a pathway for unauthorized information disclosure when accessed over an adjacent network segment.
The technical flaw stems from insufficient input validation and boundary checking mechanisms within the dhcp server codebase where integer variables are manipulated without proper overflow or underflow protection. When processing dhcp requests or responses, certain counters or sequence numbers may decrement below zero, causing the system to wrap around to maximum positive values or behave unpredictably. This condition can be triggered through crafted network packets sent by an attacker positioned within the same broadcast domain as the vulnerable dhcp server. The underlying cause aligns with common weakness enumeration CWE-191 which specifically addresses integer underflow conditions and their potential for exploitation.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks within the compromised network environment. An attacker exploiting this condition could gain insights into dhcp server internal states, sequence numbers, or other sensitive operational parameters that might aid in further exploitation attempts. The adjacent network requirement means that physical or logical proximity is necessary for exploitation, but once achieved, the vulnerability provides a foothold for reconnaissance activities and potentially more severe attacks such as man-in-the-middle positioning or disruption of dhcp services. This weakness directly correlates with attack techniques described in the attack tree framework where initial access through adjacent network positions leads to information gathering phases.
Mitigation strategies should focus on implementing comprehensive input validation procedures that include explicit checks for underflow conditions before any arithmetic operations occur. System administrators must ensure windows dhcp servers are updated with the latest security patches from microsoft, as this vulnerability is typically addressed through vendor-provided fixes. Network segmentation and access controls should be implemented to limit adjacent network access points where possible, reducing the attack surface. Additionally, monitoring systems should be configured to detect anomalous dhcp traffic patterns that might indicate exploitation attempts, while network intrusion detection systems can be tuned to identify crafted packets designed to trigger integer underflow conditions. Regular security assessments of dhcp server configurations and network infrastructure help maintain defense-in-depth approaches against this class of vulnerabilities that are categorized under the broader scope of software security flaws affecting network services.