CVE-2026-62718 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
This vulnerability represents a critical integer underflow condition within the windows dhcp server implementation that can be exploited by remote attackers within the same network segment. The flaw occurs when the dhcp server processes certain malformed packets or requests where integer arithmetic operations result in values that wrap around to smaller numbers than expected, creating unexpected behavior in memory management and packet handling routines. This type of vulnerability falls under the common weakness enumeration cw 129 which specifically addresses integer overflows and underflows in software implementations. The attack vector requires an adjacent network presence meaning the malicious actor must be on the same local network segment as the target dhcp server, typically through physical access or network infiltration techniques such as arp spoofing or vlan hopping attacks.
The technical exploitation involves crafting specially formatted dhcp packets that trigger the integer underflow condition during processing of request parameters or packet validation routines. When the dhcp server attempts to perform arithmetic operations on variables that become negative due to underflow, it can cause memory corruption patterns that may lead to information disclosure vulnerabilities. The underlying mechanism often involves buffer size calculations or counter decrements that fail to properly validate input values before performing mathematical operations. This particular vulnerability enables attackers to potentially extract sensitive information from the dhcp server memory space including configuration details, client information, or other system data that should remain confidential within the internal network infrastructure.
The operational impact of this vulnerability extends beyond simple information disclosure as it provides attackers with valuable reconnaissance data that can be used for further network infiltration attempts. An attacker who successfully exploits this condition could gain insights into dhcp server configurations, client address assignments, or network topology details that would otherwise remain hidden. This information disclosure capability aligns with several tactics described in the attack technique framework including initial access through network infiltration and privilege escalation via reconnaissance activities. The vulnerability particularly affects organizations that rely heavily on dhcp services for network management and could compromise the security posture of entire local networks if exploited successfully.
Mitigation strategies should focus on implementing proper input validation and arithmetic boundary checking within the dhcp server implementation to prevent integer underflow conditions from occurring. Network administrators should ensure that windows dhcp servers are properly patched with vendor security updates that address this specific vulnerability type. Additionally, network segmentation techniques including vlan isolation and proper access control lists can limit the attack surface by preventing adjacent network access to critical dhcp infrastructure. The implementation of intrusion detection systems specifically configured to monitor for malformed dhcp traffic patterns can help detect exploitation attempts before they succeed in extracting sensitive information. Organizations should also consider implementing network access control measures that restrict direct access to dhcp servers from untrusted network segments and maintain regular security assessments to identify potential integer overflow conditions in other network services that may present similar risks.