How severe is CVE-2018-0156?

CVE-2018-0156 has a CVSS 3.1 base score of 7.5 (HIGH). EPSS estimates a 9.4% probability of exploitation in the next 30 days. It is listed in the CISA Known Exploited Vulnerabilities catalog.

CVE-2018-0156: Cisco IOS Software and Cisco IOS XE Software Smart

CISA Known Exploited Vulnerabilities

Cisco IOS Software and Cisco IOS XE Software Smart Install Denial-of-Service Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV

2022-03-03

Remediation due

2022-03-17

Required action
Apply updates per vendor instructions.

CISA notes
https://nvd.nist.gov/vuln/detail/CVE-2018-0156

Description

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. The vulnerability is due to improper validation of packet data. An attacker could exploit this vulnerability by sending a crafted packet to an affected device on TCP port 4786. Only Smart Install client switches are affected. Cisco devices that are configured as a Smart Install director are not affected by this vulnerability. Cisco Bug IDs: CSCvd40673.

Severity

CVSS 3.1 · CISA7.5 HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC · CISA-ADP

Exploitationactive

Automatableyes

Technical impactpartial

Exploitation Context

as of October 14, 2026

All KEV statistics→

CISA added CVE-2018-0156 to the KEV catalog 1,436 days after its CVE record was published.
It is one of 100 Cisco entries in the CISA KEV catalog, and one of 50 added in 2022.
Its current EPSS score (9.4%) is higher than that of 25% of CISA KEV entries.

Affected Products

Vendor	Product	Affected versions
-	Cisco IOS and IOS XE	Cisco IOS and IOS XE

References

5 Links

Vulnerability databases

Other references

Record Details

Published

2018-03-28

Last updated

2026-01-12

Assigner (CNA)

cisco

Credited to

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Tool categories

Fuzzing

CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.

CVE-2018-0156