CVE-2017-12240criticalunder attackCWE-20

CVE-2017-12240: critical vulnerability in Cisco IOS and IOS XE

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63Vexday Risk Score

Prioritize patching. It under exploitation confirmed by CISA.

ssvc Actcvss 9.8epss 14%
from disclosure to weapon
Published on NVDSep 28
CISA KEV+1617d
Action required by CISAfederal deadline: 2022-03-24

Apply updates per vendor instructions.

In short

A buffer overflow in Cisco IOS DHCP relay allows remote attackers to send specially crafted network packets that crash the system or execute malicious code, taking complete control without requiring authentication.

Technical detail

Buffer overflow in DHCP relay subsystem (CWE-20: improper input validation) triggered by crafted DHCPv4 packets from unauthenticated remote attackers; exploitation results in arbitrary code execution or denial of service via system reload. Affects Cisco IOS 12.2–15.6 and IOS XE Software.

Summary generated and translated by AI from the official description.

The full analysis of this CVE is available in Portuguese →

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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
n/a · Cisco IOS and IOS XE