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CVE-2017-12240

Cisco IOS and IOS XE Software DHCP Remote Code Execution Vulnerability

Exploited in attacks Critical 9.8 Attack chance: 14%
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What it is

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.

CISA: The Dynamic Host Configuration Protocol (DHCP) relay subsystem of Cisco IOS 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.

What to do

Apply updates per vendor instructions.

Deadline for US federal agencies: March 24, 2022

Added to the CISA list
March 3, 2022
Published
September 28, 2017
Severity
Critical 9.8 CVSS 3.1
Chance of attacks in the next 30 days (EPSS)
14% in the top 3.5% of all known vulnerabilities
Weakness
CWE-20
More details
NVD · CVE.org · CISA
All references (5)

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Mar 3, 2022IOS Software and Cisco IOS XE Software Denial-of-ServiceCVE-2017-6663IOS and IOS XE SoftwareMedium 6.52.1%
Mar 3, 2022SNMP Remote Code ExecutionCVE-2017-6736IOS and IOS XE SoftwareHigh 8.870%
Mar 3, 2022SNMP Remote Code ExecutionCVE-2017-6737IOS and IOS XE SoftwareHigh 8.845%
Mar 3, 2022SNMP Remote Code ExecutionCVE-2017-6738IOS and IOS XE SoftwareHigh 8.811%
Mar 3, 2022SNMP Remote Code ExecutionCVE-2017-6739IOS and IOS XE SoftwareHigh 8.811%
Mar 3, 2022SNMP Remote Code ExecutionCVE-2017-6740IOS and IOS XE SoftwareHigh 8.811%

All of them →

Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.