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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 17 Mar 2022.
iOSOperating system · Cisco

CVE-2018-0158

HIGH · 8.6 CVSS v3.1 Published 2018-03-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
In the wild Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A vulnerability in the IKEv2 module of Cisco IOS Software and Cisco IOS XE Software allows an unauthenticated, remote attacker to send crafted IKEv2 packets that cause incorrect processing, leading to memory leak and eventual device reload (DoS). The vulnerability is exploitable without authentication.

MitigationApply the relevant Cisco software update/patch for Cisco IOS and IOS XE when available. Consider implementing ACLs to restrict IKEv2 traffic to trusted sources at network perimeter if the vendor recommends a workaround.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
iOSOperating system
Affected:= 15.5\(3\)s1.1= 15.5\(3\)s1.2= 15.5\(3\)s1.4= 15.5\(3\)s1.5= 15.5\(3\)s1.7= 15.5\(3\)s1.8= 15.5\(3\)s1.9= 15.5\(3\)s1.10= 15.5\(3\)s1.11= 15.5\(3\)s1.12
Ios XeOperating system
Affected:= 15.5\(3\)s1.1= 15.5\(3\)s1.2= 15.5\(3\)s1.4= 15.5\(3\)s1.5= 15.5\(3\)s1.7= 15.5\(3\)s1.8= 15.5\(3\)s1.9= 15.5\(3\)s1.10= 15.5\(3\)s1.11= 15.5\(3\)s1.12

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Cisco software type
    Run 'show version' and look for 'IOS' or 'IOS XE' in the output
    Affected if Device runs Cisco IOS or IOS XE Software
  2. Check the installed iOS or iOS XE version
    Run 'show version' and locate the version string (for example, 15.5(3)S1.1). Compare it to the affected versions: 15.5(3)S1.1, 15.5(3)S1.2, 15.5(3)S1.4, 15.5(3)S1.5, 15.5(3)S1.7, 15.5(3)S1.8, 15.5(3)S1.9, 15.5(3)S1.10, 15.5(3)S1.11, 15.5(3)S1.12
    Affected if Version matches one of the listed affected versions
  3. Determine if IKEv2 is enabled
    Run 'show crypto ikev2 sa' to check for active IKEv2 security associations, or run 'show running-config | include crypto ikev2' to check for IKEv2 configuration in the running config
    Affected if IKEv2 is configured or has active security associations on the device

Device is affected if it runs Cisco IOS or IOS XE version 15.5(3)S1.x (where x is 1, 2, 4, 5, 7, 8, 9, 10, 11, or 12) AND has IKEv2 enabled or active IKEv2 sessions.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the relevant Cisco software update/patch for Cisco IOS and IOS XE when available. Consider implementing ACLs to restrict IKEv2 traffic to trusted sources at network perimeter if the vendor recommends a workaround.

Fix this in iOS Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-0158 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data