# CVE-2018-0171 — Cisco IOS and IOS XE

**CISA KEV**

> As of 2026-01-12, CVE-2018-0171 is a HIGH-severity vulnerability in Cisco IOS and IOS XE, CVSS v3.1 7.5, EPSS 99.5% (99.9th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), with a US federal remediation deadline of 2022-05-03. Threadlinqs Intelligence links 9 tracked threat campaigns to CVE-2018-0171, most recently “US Treasury Sanctions 1VPNS VPN Service and Cryptor Seller for Enabling Ransomware Operations (linked to FSB Center 16 Router Exploitation via CVE-2018-0171/CVE-2008-4128)”.

**Last updated:** 2026-01-12

## What is CVE-2018-0171?

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.

The record classifies CVE-2018-0171 under weakness class [CWE-20](https://cwe.mitre.org/data/definitions/20.html). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 3091 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.5 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **EPSS (FIRST):** 99.5% probability of exploitation in the next 30 days, higher than 99.9% of all scored CVEs
- **CISA KEV:** Listed since 2021-11-03, federal remediation deadline 2022-05-03
- **Threadlinqs priority:** 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- **Published:** 2018-03-28, last modified 2026-01-12

## Is CVE-2018-0171 being exploited?

CISA added CVE-2018-0171 to the Known Exploited Vulnerabilities catalog on 2021-11-03, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2022-05-03 under BOD 22-01. Weaponised exploit code for CVE-2018-0171 is publicly available. 2 public proof-of-concept repositories are tracked for this identifier. A ProjectDiscovery Nuclei detection template exists (`javascript/cves/2018/CVE-2018-0171.yaml`). It currently carries a trending score of 45 in the Threadlinqs vulnerability feed.

- [AlrikRr/Cisco-Smart-Exploit](https://github.com/AlrikRr/Cisco-Smart-Exploit) (github)
- [trickest/cve](https://github.com/trickest/cve/blob/main/2018/CVE-2018-0171.md) (trickest)

## Affected products and versions

- **(vendor unspecified)**: Cisco IOS and IOS XE

## How to fix CVE-2018-0171

Vendor advisory: [https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-smi2](https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-smi2). Because CVE-2018-0171 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2022-05-03. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

## Threat activity tracking CVE-2018-0171

9 tracked threats in the Threadlinqs corpus reference CVE-2018-0171, either in the campaign’s CVE list or as an indicator on the campaign record.

- [US Treasury Sanctions 1VPNS VPN Service and Cryptor Seller for Enabling Ransomware Operations (linked to FSB Center 16 Router Exploitation via CVE-2018-0171/CVE-2008-4128)](https://intel.threadlinqs.com/threat/TL-2026-1290) — MEDIUM · 2026-07-14
- [FSB Center 16 (Static Tundra) Exploits SNMP Config Exfiltration and Cisco Smart Install RCE (CVE-2018-0171) Against Routers](https://intel.threadlinqs.com/threat/TL-2026-1312) — CRITICAL · 2026-07-14
- [CVE-2008-4128 Cisco IOS CSRF Vulnerability Added to CISA KEV — Exploited by Russian FSB Center 16 (Static Tundra / Berserk Bear) in Ongoing Router-Hygiene Espionage Campaign](https://intel.threadlinqs.com/threat/TL-2026-1272) — HIGH · 2026-07-13
- [FSB Center 16 (Static Tundra / Berserk Bear) Exploits Default/Weak SNMP and Unpatched Cisco Smart Install (CVE-2018-0171) to Compromise Networking Devices — AA26-194A](https://intel.threadlinqs.com/threat/TL-2026-1276) — HIGH · 2026-07-13
- [Russian FSB Center 16 (Static Tundra/Berserk Bear) Exploiting Unpatched Cisco Smart Install Devices — Joint NSA/FBI/13-Nation Advisory](https://intel.threadlinqs.com/threat/TL-2026-1277) — HIGH · 2026-07-13
- [NSA/FBI Joint Advisory: Disable Cisco Smart Install to Block Russian FSB "Static Tundra" Exploitation of CVE-2018-0171](https://intel.threadlinqs.com/threat/TL-2026-1279) — CRITICAL · 2026-07-13
- [Static Tundra (FSB Center 16) Exploits CVE-2018-0171 Cisco Smart Install Flaw Against Critical Infrastructure](https://intel.threadlinqs.com/threat/TL-2026-1282) — CRITICAL · 2026-07-13
- [FSB Centre 16 (Berserk Bear/Static Tundra) Targets Critical Infrastructure via Weak SNMP Credentials and Cisco Smart Install Exploitation (CVE-2018-0171) — UK/EU Attribute December 2025 Poland Energy Grid Attack](https://intel.threadlinqs.com/threat/TL-2026-1283) — HIGH · 2026-07-13
- [FSB Centre 16 (Berserk Bear/Energetic Bear) targets global critical national infrastructure via vulnerable routers — joint UK & allied advisory](https://intel.threadlinqs.com/threat/TL-2026-2375) — HIGH · 2026-07-13

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, GitHub Security Advisories, public proof-of-concept repositories, ProjectDiscovery Nuclei. Last verified by Threadlinqs on 2026-07-14. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [tools.cisco.com](https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-smi2)

**Vulnerability database entry**

- [securitytracker.com — vdb entry](http://www.securitytracker.com/id/1040580)
- [securityfocus.com — vdb entry](http://www.securityfocus.com/bid/103538)

**Other references**

- [ics-cert.us-cert.gov](https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04)
- [darkreading.com](https://www.darkreading.com/perimeter/attackers-exploit-cisco-switch-issue-as-vendor-warns-of-yet-another-critical-flaw/d/d-id/1331490)
- [ics-cert.us-cert.gov (ICSA 18 107 05)](https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05)

Canonical: https://intel.threadlinqs.com/cve/CVE-2018-0171
Full detection coverage and IOCs for threats exploiting CVE-2018-0171 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp