CVE-2017-12240
Cisco IOS and IOS XE Software DHCP Remote Code Execution Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 24 March 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 13.77% probability · 96th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 3 March 2022 · due 24 March 2022
- Weakness
- CWE-20, CWE-119
- Affected
- cisco/ios
- Source
- psirt@cisco.com
EPSS 13.8% since 27 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2017-12240
References
- http://www.securityfocus.com/bid/101034Broken Link, Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1039445Broken Link, Third Party Advisory, VDB Entry
- https://quickview.cloudapps.cisco.com/quickview/bug/CSCsm45390Vendor Advisory
- https://quickview.cloudapps.cisco.com/quickview/bug/CSCuw77959Vendor Advisory
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-dhcpVendor Advisory
- http://www.securityfocus.com/bid/101034Broken Link, Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1039445Broken Link, Third Party Advisory, VDB Entry
- https://quickview.cloudapps.cisco.com/quickview/bug/CSCsm45390Vendor Advisory
- https://quickview.cloudapps.cisco.com/quickview/bug/CSCuw77959Vendor Advisory
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-dhcpVendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12240US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.