ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2018-0159

Cisco IOS and XE Software Internet Key Exchange Version 1 Denial-of-Service Vulnerability

Published Mar 28, 2018 · catalog updated Jun 16, 2026 · Cisco IOS and IOS XE

Patch now

CVE-2018-0159 is in the CISA known-exploited catalog, due Mar 17, 2022. Confirm Cisco IOS and IOS XE against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
High7.5
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
6.87%
Remediation
Remediation guidance
Affected products
cpe cisco/ios · cpe cisco/ios xe · vendor Cisco IOS Software and Cisco IOS XE Software · vendor Cisco IOS and IOS XE

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe cisco/ios15.3\(3\)s
  • cpe cisco/ios xe15.3\(3\)s
  • vendor Cisco IOS Software and Cisco IOS XE Softwareversion unspecified
  • vendor Cisco IOS and IOS XEversion unspecified

How to fix CVE-2018-0159

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2018-0159 is in the CISA known-exploited catalog, due Mar 17, 2022. Confirm Cisco IOS and IOS XE against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with cisco/ios xe 15.3\(3\)s. Apply updates per vendor instructions.

What should an analyst verify?

CWE-20: Improper Input Validation. EPSS 6.87%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Cisco security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 28, 2018 · Catalog

    Detected

    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

  2. Mar 3, 2022 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Mar 17, 2022 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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

Sources

  • CISA KEVConfirmed exploitationCVE-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.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2018-0159

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2018-0159

    30-day exploitation probability 6.9%

    first.org
  • NIST NVDVulnerability recordCVE-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.

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-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.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.