CVE-2018-0172
A vulnerability in the DHCP option 82 encapsulation functionality of Cisco IOS Software and Cisco IOS XE Software could allow for denial-of-service (DoS).
A vulnerability in the DHCP option 82 encapsulation functionality of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability exists because the affected software performs incomplete input validation of option 82 information that it receives in DHCP Version 4 (DHCPv4) packets from DHCP relay agents. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device. A successful exploit could allow the attacker to cause a heap overflow condition on the affected device, which will cause the device to reload and result in a DoS condition. Cisco Bug IDs: CSCvg62730.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H- securityfocus.com/bid/103552Third Party AdvisoryVDB Entry
- securitytracker.com/id/1040591Third Party AdvisoryVDB Entry
- ics-cert.us-cert.gov/advisories/ICSA-18-107-04Third Party AdvisoryUS Government Resource
- ics-cert.us-cert.gov/advisories/ICSA-18-107-05Third Party AdvisoryUS Government Resource
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr1Vendor Advisory
- tenable.com/security/research/tra-2018-06Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0172US Government Resource
Actively exploited. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1684 days
- CVSS
- 8.6 HIGH
- EPSS (30-day exploit probability)
- 7.8% · top 5% of all CVEs
- Weakness
- CWE-20
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.