CVE-2024-26212

What it actually does

This vulnerability affects the DHCP Server service and can be exploited remotely over the network without authentication or user interaction. The CVSS vector indicates low attack complexity and high availability impact, with no direct confidentiality or integrity impact. Successful exploitation causes the DHCP Server service to stop responding, crash, or otherwise become unable to provide DHCP functionality, preventing clients from obtaining or renewing IP configuration.

Why it matters to the business

If exploited, this flaw can disrupt network connectivity for systems that rely on DHCP for IP addresses, gateways, DNS settings, or lease renewal. The practical impact may include workstation outages, failed device onboarding, degraded branch or office connectivity, and interruptions to services that depend on dynamic network configuration. Because the EPSS score is elevated, organizations operating exposed or reachable DHCP Server services should treat remediation as time-sensitive even though the vulnerability is not currently listed in CISA KEV and is not known to be used in ransomware campaigns.

How an attack unfolds

An attacker identifies a reachable DHCP Server service and sends specially crafted DHCP traffic designed to trigger the denial-of-service condition. Because exploitation requires no authentication and no user interaction, the attacker only needs network-level access to the service path. If the malicious traffic is accepted by the vulnerable service, the DHCP Server service may crash, hang, or stop processing requests. Clients then fail to receive new leases or renew existing leases, which can lead to progressive network disruption as leases expire or devices reconnect.

How to fix it

Apply the vendor security update that fixes CVE-2024-26212 for the affected DHCP Server implementation. If exact fixed product versions are not available from the provided input, use the vendor’s April 2024 security updates and product-specific advisories as the source of truth. Where immediate patching is not possible, reduce exposure by ensuring DHCP Server services are reachable only from trusted network segments, blocking untrusted DHCP traffic at network boundaries, disabling unnecessary DHCP Server instances, and monitoring for abnormal DHCP request volume or service instability. Ensure DHCP redundancy or failover is configured where operationally required.

How to confirm the fix worked

Confirm that all systems running the DHCP Server service have the applicable vendor security update installed. Verify the DHCP Server service version/build against vendor guidance, confirm the service remains stable under normal DHCP request and lease-renewal activity, and test that clients can obtain and renew leases successfully. Validate network controls by confirming that DHCP traffic is accepted only from expected local or relay paths and is not reachable from untrusted networks. Review vulnerability scanner results and patch inventory for continued exposure.

Typical attack path

1. Identify networks where a vulnerable DHCP Server service is reachable.
2. Send crafted DHCP packets to the DHCP Server service over the network.
3. Trigger the service fault condition that causes DHCP processing to fail, hang, or crash.
4. Prevent clients from obtaining or renewing DHCP leases.
5. Sustain or repeat traffic to prolong the denial of service until the service is restarted, patched, or isolated.

How to detect it

To determine whether exploitation may already have occurred, review DHCP Server operational logs, system event logs, service control logs, and network telemetry around any unexplained DHCP outages, service crashes, or spikes in DHCP traffic. Look for DHCP Server service termination, unexpected restarts, application crashes, repeated malformed or unusual DHCP requests, lease exhaustion-like symptoms without normal growth patterns, and bursts of traffic from a single host or unexpected segment. Network packet captures and flow records can help identify repeated DHCP discovery/request traffic or anomalous packets targeting DHCP server ports. Correlate client connectivity complaints, lease renewal failures, and DHCP Server service instability with inbound DHCP traffic immediately before the outage.

• DHCP Server service terminated unexpectedly
• DHCP Server service stopped
• DHCP Server service started
• The DHCP Server service terminated unexpectedly
• The DHCP Server service entered the stopped state
• The DHCP Server service entered the running state
• Event ID 7031
• Event ID 7036
• Event ID 1000
• Event ID 1001
• dhcpssvc
• UDP/67
• UDP/68
• DHCPDISCOVER
• DHCPREQUEST
• DHCP Server

What your security team should do

• Prioritize patching DHCP Server systems because exploitation is remote, unauthenticated, low-complexity, and has high availability impact.
• Inventory all DHCP Server instances, including backup, branch, lab, and disaster recovery systems.
• Restrict DHCP Server exposure to trusted segments and authorized relay agents only.
• Enable or verify DHCP failover, redundancy, and operational recovery procedures to reduce outage impact.
• Monitor DHCP Server health, crash events, service restarts, and abnormal request spikes.
• Review firewall, router, and relay configurations to prevent DHCP traffic from untrusted networks reaching the service.
• If patching is delayed, increase monitoring and prepare rapid restart or failover procedures for DHCP service disruption.