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HIGH severity

CVE-2018-0158 — IOS

HIGH

CVE-2018-0158 is a high-severity (CVSS 8.6) Improper Input Validation vulnerability in cisco ios. 2 public exploit references exist, so weaponization risk is real. No vendor fix is recorded yet; mitigation options are listed below.

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a memory…

Published
Updated
Affected
2 products
Patched
See advisory
Exploits
2 known
Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

  • CISA’s SSVC triage classifies this CVE as under active exploitation.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for CVE-2018-0158.

EPSS Exploitation Probability

via FIRST.org ↗
7.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs94th percentile — riskier than 94% of all scored CVEsHighest risk
4.98%8.91%12.8%16.8%14.6%7.2%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2018-0158 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 395,249 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Description

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a memory leak or a reload of an affected device that leads to a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device to be processed. A successful exploit could cause an affected device to continuously consume memory and eventually reload, resulting in a DoS condition. Cisco Bug IDs: CSCvf22394.

Affected Products

2 products · 40 configurations
OS
ioscisco
10 versions
15.5\(3\)s1.115.5\(3\)s1.215.5\(3\)s1.415.5\(3\)s1.515.5\(3\)s1.715.5\(3\)s1.815.5\(3\)s1.915.5\(3\)s1.1015.5\(3\)s1.1115.5\(3\)s1.12
OS
ios xecisco
10 versions
15.5\(3\)s1.115.5\(3\)s1.215.5\(3\)s1.415.5\(3\)s1.515.5\(3\)s1.715.5\(3\)s1.815.5\(3\)s1.915.5\(3\)s1.1015.5\(3\)s1.1115.5\(3\)s1.12
Exploits & PoCs
2

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

Detection & mitigation playbook

Vendor / appliance
  1. Detect

    Inventory every cisco ios deployment and check each version against the affected-products list above.

  2. Remediation status

    No patch has shipped for CVE-2018-0158 yet — track the cisco ios advisory for a fixed release and apply the workarounds below in the meantime.

  3. Mitigate without a patch

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Frequently Asked Questions

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a memory leak or a reload of an affected device that leads to a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device to be processed. A successful exploit could cause an affected device to continuously consume memory and eventually reload, resulting in a DoS condition
O3 Security · Runtime Protection

Is CVE-2018-0158 being exploited in your environment?

Detect and block the exploit chain at execution, on systems you cannot patch yet.

Actively Exploited: CVE-2018-0158: IOS (High 8.6)