CVE-2017-12240

CRITICAL severity · CVSS 9.8 · Improper input validation · actively exploited (CISA KEV)

9.8CVSS CRITICAL ● exploited

🔴 Actively exploited in the wild (CISA Known Exploited Vulnerabilities). Added to KEV 2022-03-03. US federal agencies must patch by 2022-03-24.

Summary

The DHCP relay subsystem of Cisco IOS 12.2 through 15.6 and Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code and gain full control of an affected system. The attacker could also cause an affected system to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to a buffer overflow condition in the DHCP relay subsystem of the affected software. An attacker could exploit this vulnerability by sending a crafted DHCP Version 4 (DHCPv4) packet to an affected system. A successful exploit could allow the attacker to execute arbitrary code and gain full control of the affected system or cause the affected system to reload, resulting in a DoS condition. Cisco Bug IDs: CSCsm45390, CSCuw77959.

Impact & exploitability

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

Confidentiality impactHigh

Integrity impactHigh

Availability impactHigh

Exploit probability (EPSS)11%

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products we track (1)

Cisco IOS

Recommendation

This vulnerability is being actively exploited in the wild — patch affected products urgently. Open any affected product above for its exact safe version.

CVE-2017-12240

Summary

Impact & exploitability

Affected products we track (1)

Recommendation

Additional information