How severe is CVE-2018-0156?

CVE-2018-0156 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2018-0156?

Affected package information for CVE-2018-0156 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2018-0156?

No fixed version has been published for CVE-2018-0156 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2018-0156 actively exploited in the wild?

Yes. There are 2 known exploit references for CVE-2018-0156, including 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2018-0156?

CVE-2018-0156 has an EPSS (Exploit Prediction Scoring System) score of 15.5%, placing it in the 95th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

Is CVE-2018-0156 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2018-0156 (Cisco IOS Software and Cisco IOS XE Software Smart Install Denial-of-Service Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2022-03-03. CISA required all US federal civilian agencies to remediate this vulnerability by 2022-03-17. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2018-0156?

CVE-2018-0156 is classified as CWE-399 (CWE-399), Improper Input Validation (CWE-20). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2018-0156?

CVE-2018-0156 affects cisco ios (2 versions, e.g. 15.2\(2\)e4, 15.2\(2a\)ja); cisco ios xe (2 versions, e.g. 15.2\(2\)e4, 15.2\(2a\)ja). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2018-0156 published, and has it been updated?

CVE-2018-0156 was published on March 28, 2018 and was last updated on January 13, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2022-03-03 — agencies required to remediate by 2022-03-17

CVE-2018-0156

HIGH

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,…

Published

Mar 28, 2018

Updated

Jan 13, 2026

Affected

0 pkgs

Patched

None yet

Exploits

2 known

EPSS Exploitation Probability

via FIRST.org ↗

15.5%probability of exploitation in next 30 days

Moderate Risk95th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

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.

Affected Products

2 products · 4 configurations

ioscisco

2 versions

15.2\(2\)e415.2\(2a\)ja

ios xecisco

2 versions

15.2\(2\)e415.2\(2a\)ja

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

A vulnerability in the Smart Install feature of Cisco IOS Software and C…

research.kudelskisecurity.comAPIApr 2018

A vulnerability in the Smart Install feature of Cisco IOS Software and C…

cisa.govCISAMar 2022

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2018-0156 in your stack?

O3 detects CVE-2018-0156 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my stack How O3 SCA works

CVSS Score

7.5/10

CVSS v3 base score

Vector breakdown

AV:Attack Vector

Network

AC:Attack Complexity

Low

PR:Privileges Required

None

UI:User Interaction

None

S:Scope

Unchanged

C:Confidentiality

None

I:Integrity

None

A:Availability

High

Raw vector

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

CWE Classification

CWE-399CWE-399 CWE-20Improper Input Validation

Weaponization

No known public exploit tooling found.

Timeline

Disclosed

Mar 28, 2018

First exploit

Apr 7, 2018

KEV added

Mar 3, 2022

Last updated

Jan 13, 2026

Identifiers

CVE-2018-0156

References

Advisorysecurityfocus.com Advisorysecuritytracker.com Advisoryics-cert.us-cert.gov Advisoryics-cert.us-cert.gov Advisorytools.cisco.com Advisorysecurityfocus.com Advisorysecuritytracker.com Advisoryics-cert.us-cert.gov Advisoryics-cert.us-cert.gov Advisorytools.cisco.com Webcisa.gov

Data from OSV.dev, enriched by O3 Security. Refreshed hourly.