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iOSOperating system · Cisco

CVE-2020-3230

HIGH · 7.5 CVSS v3.1 Published 2020-06-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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) implementation in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to prevent IKEv2 from establishing new security associations. The vulnerability is due to incorrect handling of crafted IKEv2 SA-Init packets. An attacker could exploit this vulnerability by sending crafted IKEv2 SA-Init packets to the affected device. An exploit could allow the attacker to cause the affected device to reach the maximum incoming negotiation limits and prevent further IKEv2 security associations from being formed.

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

Denial of service vulnerability in Cisco IOS/IOS XE IKEv2 implementation where malformed SA-Init packets cause the device to hit maximum incoming negotiation limits, blocking all subsequent IKEv2 security association establishments.

MitigationApply Cisco-supplied software updates for IOS/IOS XE; as interim measures, implement network-level filtering or rate limiting for IKEv2 traffic at perimeter devices.

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:= 12.2\(6\)i1= 15.0\(2\)ej= 15.0\(2\)ej1= 15.0\(2\)ek= 15.0\(2\)ek1= 15.0\(2\)ex= 15.0\(2\)ex1= 15.0\(2\)ex2= 15.0\(2\)ex3= 15.0\(2\)ex4= 15.0\(2\)ex5= 15.0\(2\)ex6
Ios XeOperating system
Affected:= 3.3.0sg= 3.3.0xo= 3.3.1sg= 3.3.1xo= 3.3.2sg= 3.3.2xo= 3.4.0sg= 3.4.1sg= 3.4.2sg= 3.4.3sg= 3.4.4sg= 3.4.5sg

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
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 product and platform type
    Run 'show version' command and look for 'Cisco IOS' or 'Cisco IOS XE' in the output. Note the software name string.
    Affected if The device is running Cisco IOS or Cisco IOS XE software.
  2. Check the installed IOS/IOS XE version
    Run 'show version' and locate the version number in the output. Compare this version against the affected ranges: Cisco iOS versions 12.2(6)i1, 15.0(2)ej through 15.0(2)ex6; Cisco IOS XE versions 3.3.0sg through 3.4.5sg.
    Affected if The installed version exactly matches one of the listed affected versions.
  3. Verify IKEv2 is configured
    Run 'show crypto ikev2 sa' or 'show ip interface' to check for active IKEv2 security associations or IKEv2 configuration. Also run 'show crypto isakmp sa' to view ISAKMP/IKEv2 status.
    Affected if IKEv2 is actively configured or there are existing IKEv2 security associations on the device.
  4. Check for DoS symptoms in logs
    Run 'show logging' or 'show log' to review system logs for error messages related to IKEv2 negotiation failures, maximum limits reached, or unusual IKEv2 activity patterns.
    Affected if Logs show IKEv2 negotiation failures, messages about reaching maximum incoming negotiation limits, or inability to establish new IKEv2 security associations.

A device is affected if it runs one of the listed Cisco IOS or IOS XE versions AND has IKEv2 enabled, with logs potentially showing symptoms of the DoS condition.

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 Cisco-supplied software updates for IOS/IOS XE; as interim measures, implement network-level filtering or rate limiting for IKEv2 traffic at perimeter devices.

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,820
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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-2020-3230 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