CVE-2017-12240

CRITICAL9.8

CISA KEV

Published 2017-09-29 · Updated 2026-06-17 · Source psirt@cisco.com

Summary

CVE-2017-12240 is a critical-severity (CVSS 9.8) vulnerability in Cisco IOS and IOS XE Software. CISA added it to the Known Exploited Vulnerabilities catalog on March 3, 2022, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by March 24, 2022. CISA does not currently list it as used in ransomware campaigns. Cisco has 102 vulnerabilities in the KEV catalog, 7 of them linked to ransomware.

All 102 known-exploited Cisco vulnerabilities →

Description

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

CWE-20CWE-119

CISA Known-Exploited Vulnerability

Product: Cisco — IOS and IOS XE Software

Name: Cisco IOS and IOS XE Software DHCP Remote Code Execution Vulnerability

Date added: 2022-03-03 · Due: 2022-03-24

Required action: Apply updates per vendor instructions.

References

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