High 7.5Known exploited (CISA KEV)Published Mar 28, 2018

CVE-2018-0159A 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…

Updated under an hour ago (2026-10-19 08:40 UTC)

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It affects cisco ios and 1 other product. Add what you run to find out whether that includes you.

CISA lists it as known exploited since Mar 3, 2022; federal agencies had to remediate by Mar 17, 2022. Treat that date as your deadline.

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Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-20
Known exploited: Added to CISA KEV Mar 3, 2022; federal remediation due Mar 17, 2022Apply updates per vendor instructions.
EPSS (exploitation in the next 30 days): 6.87% (percentile 94)
Assigned by: cisco
NVD analysis: Analyzed
Record last updated: Jan 12, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

cisco ios cisco:ios	15.3(3)s	NVD
cisco ios_xe cisco:ios_xe	15.3(3)s	NVD

References

http://www.securityfocus.com/bid/103562vdb-entry, x-refsource-bid, broken-link, third-party-advisory
http://www.securitytracker.com/id/1040595vdb-entry, x-refsource-sectrack, broken-link, third-party-advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-ike-dosx-refsource-confirm, vendor-advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0159us-government-resource

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.