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.
Conclusion & alert: CVE-2018-0171 is rated Critical Active Threat (99/100): CVSS Critical severity, with high exploitation likelihood (EPSS 92.90%, 100th percentile). Core evidence: CISA KEV confirms active exploitation (added 2021-11-03) affecting Cisco / IOS and IOS XE. a weakness (CWE-20) Unauthenticated remote administrative access may be possible. Mandatory action: The CISA remediation deadline has passed—treat as an emergency patch priority.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
: Cisco IOS and IOS XE Software Smart Install Remote Code Execution Vulnerability · CISA KEV detail
: 2021-11-03
: 2022-05-03
: Apply updates per vendor instructions.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| 44451 | exploit_db | edb | 2018-03-29 | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-22 | 93.03% | 92.90% | -0.13% |
| 2 | 2026-05-11 | 92.67% | 93.03% | +0.36% |
| 3 | 2026-04-28 | — | 92.67% | — |
Full EPSS history (75 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| 10.0 | 2.0 | HIGH |
|
10.0 | 10.0 | [email protected] |
| URL | Tags |
|---|---|
| http://www.securityfocus.com/bid/103538 | Third Party Advisory VDB Entry |
| http://www.securitytracker.com/id/1040580 | Third Party Advisory VDB Entry |
| https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04 | Third Party Advisory US Government Resource |
| https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05 | Third Party Advisory US Government Resource |
| https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-smi2 | Vendor Advisory |
| https://www.darkreading.com/perimeter/attackers-exploit-cisco-switch-issue-as-vendor-warns-of-yet-another-critical-flaw/d/d-id/1331490 | Press/Media Coverage |
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0171 | US Government Resource |