CVE-2026-62716 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 unauthorized attackers positioned on the same network segment. The flaw occurs when the dhcp server processes certain packet structures containing malformed integer values that cause arithmetic operations to wrap around to unexpectedly low values, creating a scenario where the server fails to properly validate input data before performing critical operations. This particular vulnerability falls under the common weakness enumeration category CWE-191 Integer Underflow (Wrap or Wraparound) which specifically addresses situations where integer operations produce results that are smaller than the minimum value representable by the data type.
The technical exploitation of this vulnerability requires an attacker to be positioned on the adjacent network and send specially crafted dhcp packets to the target server. When the dhcp server processes these malformed packets, it performs arithmetic calculations on integer values that result in underflow conditions, potentially causing memory access violations or information disclosure mechanisms to be triggered. The underlying flaw stems from inadequate input validation and boundary checking within the dhcp server's packet parsing routines, where unsigned integers are not properly constrained before being used in critical operations such as buffer size calculations or loop counters.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks including remote code execution or denial of service conditions. An attacker could leverage this weakness to manipulate the dhcp server's internal state, potentially causing it to allocate memory incorrectly or to process packets in unexpected ways that could lead to system instability or privilege escalation. The adjacent network requirement limits the attack surface but does not eliminate the risk since local network access is often more easily achieved than remote access in enterprise environments.
Mitigation strategies should focus on implementing proper input validation and boundary checking mechanisms within the dhcp server software, ensuring that all integer operations are checked against expected ranges before execution. Network segmentation and access control measures including firewall rules to restrict dhcp server communication to authorized network segments can significantly reduce the attack surface. Additionally, regular security updates from microsoft addressing this specific vulnerability should be implemented immediately upon release, as this type of integer underflow vulnerability typically requires patching at the software level rather than network configuration changes. Organizations should also implement network monitoring solutions capable of detecting anomalous dhcp traffic patterns that could indicate exploitation attempts and establish baseline network behavior for comparison against potential attack signatures. The vulnerability demonstrates the importance of robust input validation in server applications and aligns with ATT&CK technique T1071.004 Application Layer Protocol: DNS where attackers may leverage protocol parsing weaknesses to gain unauthorized access or information disclosure from network services.