Cisco · IOS and IOS XE
CVE-2018-0171
Cisco IOS and IOS XE Software Smart Install Remote Code Execution Vulnerability
What it is
A vulnerability in the Smart Install feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition, or to execute arbitrary code on an affected device. The vulnerability is due to improper validation of packet data. An attacker could exploit this vulnerability by sending a crafted Smart Install message to an affected device on TCP port 4786. A successful exploit could allow the attacker to cause a buffer overflow on the affected device, which could have the following impacts: Triggering a reload of the device, Allowing the attacker to execute arbitrary code on the device, Causing an indefinite loop on the affected device that triggers a watchdog crash. Cisco Bug IDs: CSCvg76186.
CISA: Cisco IOS and IOS XE Software improperly validates packet data, allowing an unauthenticated, remote attacker to trigger a reload of an affected device, cause a denial-of-service (DoS) condition, or perform code execution on the affected device.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: May 3, 2022
- Added to the CISA list
- November 3, 2021
- Published
- March 28, 2018
- Severity
- High 7.5 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 99.5% in the top 0.1% of all known vulnerabilities
- Weakness
- CWE-20
- More details
- NVD · CVE.org · CISA
All references (6)
- https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04
- http://www.securitytracker.com/id/1040580
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-smi2
- https://www.darkreading.com/perimeter/attackers-exploit-cisco-switch-issue-as-vendor-warns-of-yet-another-cri…
- https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05
- http://www.securityfocus.com/bid/103538
More exploited flaws from Cisco
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Sep 29, 2025 | Software SNMP Denial of Service and Remote Code Execution | IOS and IOS XE | High 7.7 | 42% |
| Oct 10, 2023 | Group Encrypted Transport VPN Out-of-Bounds Write | IOS and IOS XE | Medium 6.6 | 2.5% |
| Mar 25, 2022 | Remote Code Execution | IOS and IOS XE | Critical 9.8 | 99% |
| Oct 14, 2026 | Relative Path Traversal | Secure Email Gateway | Critical 9.8 | 2.2% |
| Sep 30, 2026 | Hex Encoding | Catalyst SD-WAN Manager | Critical 9.8 | 39% |
| Sep 16, 2026 | Incorrect Use of Privileged APIs | Identity Services Engine | Critical 10.0 | 76% |
| Sep 14, 2026 | SQL Injection | Secure Email Gateway | Critical 9.8 | 30% |
| Sep 9, 2026 | Firewall Management Center Authentication Bypass Using an Alternate Path or Channel | Secure Firewall Management Center (FMC) and Security Cloud Control (SCC) Firewall Management | Critical 10.0 | 88% |
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.