CVE-2018-0156
HighExploitedPublic exploitA 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.
Published Mar 28, 2018 · Updated Jan 13, 2026
Key Facts
Patch immediately- CVE-2018-0156 is a high-severity vulnerability (CVSS 7.5 v3.1) affecting IOS (Cisco), IOS Xe (Cisco), Cisco IOS and IOS XE.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 3, 2022. Public exploit code is available.
- EPSS estimates a 9.4% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (30-day exploit likelihood)
9.4%
Higher than 95.3% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2018-0156 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Mar 3, 2022 | Mar 17, 2022 | Not reported |
| Industry KEV feed | Mar 3, 2022 | Mar 17, 2022 | Not reported |
| CIRCL KEV | Mar 3, 2022 | Mar 17, 2022 | Not reported |
| ENISA EUVD | Mar 3, 2022 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
5 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| IOSCisco | 15.2\(2a\)ja, 15.2\(2\)e4 | n/a |
| IOS XeCisco | 15.2\(2a\)ja, 15.2\(2\)e4 | n/a |
| Cisco IOS and IOS XE | >= Cisco IOS and IOS XE | n/a |
Timeline
Publicly disclosed
Mar 28, 2018
Added to CISA KEV
Mar 3, 2022
Added to Industry KEV feed
Mar 3, 2022
Added to CIRCL KEV
Mar 3, 2022
Added to ENISA EUVD
Mar 3, 2022
Last updated
Jan 13, 2026
Weakness Type
- CWE-20 Improper Input Validation
- CWE-399
References
- advisoryhttps://ics-cert.us-cert.gov/advisories/ICSA-18-107-04
- advisoryhttps://ics-cert.us-cert.gov/advisories/ICSA-18-107-05
- advisoryhttps://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-smi
- advisory103569
- advisory1040596
FAQ
Common Questions.
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.
Affected: IOS (Cisco) versions 15.2\(2a\)ja, 15.2\(2\)e4; IOS Xe (Cisco) versions 15.2\(2a\)ja, 15.2\(2\)e4; Cisco IOS and IOS XE versions >= Cisco IOS and IOS XE. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 3, 2022.
Yes. It was added on Mar 3, 2022 with a federal remediation due date of Mar 17, 2022.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Is CVE-2018-0156 Running On Your Attack Surface?
Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.
Request A Demo