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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 24 Mar 2022.
iOSOperating system · Cisco

CVE-2017-6663

MEDIUM · 6.5 CVSS v3.1 Published 2017-08-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
99/100
Remediation priority · Urgent
In the wild 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 Autonomic Networking feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause autonomic nodes of an affected system to reload, resulting in a denial of service (DoS) condition. More Information: CSCvd88936. Known Affected Releases: Denali-16.2.1 Denali-16.3.1.

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

This is a vulnerability in Cisco IOS and IOS XE Software's Autonomic Networking feature. An unauthenticated attacker on the adjacent network segment can exploit this flaw to cause affected devices to reload, resulting in denial of service. The attack does not require authentication but requires the attacker to be on the same network segment as the vulnerable devices.

MitigationIf Autonomic Networking is not required in the environment, disable the feature. Otherwise, apply Cisco's patched software releases when available. Implement network segmentation to limit adjacent attacker access to the autonomic infrastructure.

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:= 15.2\(3\)e= 15.2\(3\)e1= 15.2\(3\)e2= 15.2\(3\)e3= 15.2\(3\)e4= 15.2\(3\)e5= 15.2\(3a\)e= 15.2\(3a\)e1= 15.2\(3m\)e2= 15.2\(3m\)e3= 15.2\(3m\)e6= 15.2\(3m\)e8
Ios XeOperating system
Affected:= 3.7.0e= 3.7.1e= 3.7.3e= 3.8.0e= 3.8.0ex= 3.8.1e= 3.8.2e= 3.8.3e= 3.9.0e= 3.9.1e= 3.10.4s= 3.10.8as

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/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. Determine the Cisco IOS or IOS XE version
    Run 'show version' on the device CLI and locate the version string in the output (e.g., 'Version 15.2(3)e' or 'Version 03.10.04s')
    Affected if The displayed version matches any of the listed affected versions: 15.2(3)e through 15.2(3m)e8 for iOS, or 3.7.0e through 3.10.8as for IOS XE
  2. Verify if Autonomic Networking is enabled
    Run 'show running-config | include autonomic' or 'show autonomic' in the device CLI to check for Autonomic Networking configuration
    Affected if Autonomic Networking is actively enabled or configured on the device
  3. Confirm the device is reachable on the local segment
    Verify network accessibility from an adjacent attacker perspective - the device must have Layer 2 adjacency with untrusted hosts
    Affected if The device is on a network segment where untrusted/unauthenticated hosts can directly communicate with it (same broadcast domain/VLAN)

The device is affected if it runs one of the listed vulnerable versions AND has Autonomic Networking enabled AND is exposed to adjacent network attackers.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

If Autonomic Networking is not required in the environment, disable the feature. Otherwise, apply Cisco's patched software releases when available. Implement network segmentation to limit adjacent attacker access to the autonomic infrastructure.

Recommended fix Moderate confidence

Obtain fixed release from Cisco security advisory for CVE-2017-6663 (specific version varies by platform - check tools.cisco.com)

  1. 1. Identify the current Cisco IOS or IOS XE version running on the affected device using 'show version' command
  2. 2. Access Cisco's official security advisory for CVE-2017-6663 at tools.cisco.com to obtain the specific fixed release for your device platform
  3. 3. Plan maintenance window as the upgrade will require device reload
  4. 4. Backup current device configuration using 'copy running-config startup-config' or export via TFTP/FTP
  5. 5. Download the recommended fixed IOS/IOS XE release from Cisco's software center
  6. 6. Upgrade the device using appropriate method (TFTP, FTP, USB, or Cisco Prime Infrastructure)
  7. 7. After upgrade, verify the new version is installed with 'show version'
  8. 8. Confirm autonomic networking functionality is operational
Caveat Standard upgrade risks apply - ensure configuration compatibility and plan for downtime

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in iOS Exploited in the wild — priority engagement
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,580
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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-2017-6663 in production — separate from our analysis above.

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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