How severe is CVE-2018-0156?

CVE-2018-0156 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-0156 being actively exploited?

Yes. CVE-2018-0156 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-03-03, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2018-0156?

CVE-2018-0156 primarily affects Cisco Ios. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-0156?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2018-0156 have an EU (EUVD) identifier?

Yes. CVE-2018-0156 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2018-0979. It is also flagged as exploited in the EUVD (since 2022-03-03).

When was CVE-2018-0156 published?

CVE-2018-0156 was published on 2018-03-28 and last updated on 2026-06-17.

CVE-2018-0156

CVE-2018-0156 is a high-severity vulnerability in Cisco Ios with a CVSS 3.x base score of 7.5. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2022-03-03). The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 7.8
EPSS exploit prediction: 8% (94th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2022-03-03)
EU (EUVD) id: EUVD-2018-0979
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2022-03-03)
Weakness: CWE-20
Affected product: Cisco Ios
Published: 2018-03-28
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2018-0156?: 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.
How severe is CVE-2018-0156?: CVE-2018-0156 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-0156 being actively exploited?: Yes. CVE-2018-0156 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-03-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2018-0156?: CVE-2018-0156 primarily affects Cisco Ios. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-0156?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2018-0156 have an EU (EUVD) identifier?: Yes. CVE-2018-0156 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2018-0979. It is also flagged as exploited in the EUVD (since 2022-03-03).
When was CVE-2018-0156 published?: CVE-2018-0156 was published on 2018-03-28 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:o:cisco:ios:15.2\(2\)e4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:15.2\(2a\)ja:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:15.2\(2\)e4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:15.2\(2a\)ja:*:*:*:*:*:*:*

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