How severe is CVE-2018-0159?

CVE-2018-0159 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-2018-0159 being actively exploited?

Yes. CVE-2018-0159 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-2018-0159?

CVE-2018-0159 primarily affects Cisco Ios. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-0159?

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-2018-0159 have an EU (EUVD) identifier?

Yes. CVE-2018-0159 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2018-0982. It is also flagged as exploited in the EUVD (since 2022-03-03).

When was CVE-2018-0159 published?

CVE-2018-0159 was published on 2018-03-28 and last updated on 2026-06-17.

CVE-2018-0159

CVE-2018-0159 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: 7% (93rd percentile)
Actively exploited: Yes — listed in CISA KEV (added 2022-03-03)
EU (EUVD) id: EUVD-2018-0982
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 implementation of Internet Key Exchange Version 1 (IKEv1) functionality in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of specific IKEv1 packets. An attacker could exploit this vulnerability by sending crafted IKEv1 packets to an affected device during an IKE negotiation. A successful exploit could allow the attacker to cause an affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCuj73916.

Frequently asked questions

What is CVE-2018-0159?: A vulnerability in the implementation of Internet Key Exchange Version 1 (IKEv1) functionality in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of specific IKEv1 packets. An attacker could exploit this vulnerability by sending crafted IKEv1 packets to an affected device during an IKE negotiation. A successful exploit could allow the attacker to cause an affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCuj73916.
How severe is CVE-2018-0159?: CVE-2018-0159 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-2018-0159 being actively exploited?: Yes. CVE-2018-0159 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-2018-0159?: CVE-2018-0159 primarily affects Cisco Ios. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-0159?: 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-2018-0159 have an EU (EUVD) identifier?: Yes. CVE-2018-0159 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2018-0982. It is also flagged as exploited in the EUVD (since 2022-03-03).
When was CVE-2018-0159 published?: CVE-2018-0159 was published on 2018-03-28 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:cisco:ios:15.3\(3\)s:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:15.3\(3\)s:*:*:*:*:*:*:*

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