dbcve.org
Asr 5000 Series SoftwareApplication · Cisco

CVE-2016-6467

HIGH · 7.5 CVSS v3.0 Published 2016-12-14
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 IPv6 packet fragment reassembly of StarOS for Cisco Aggregation Services Router (ASR) 5000 Series Switch could allow an unauthenticated, remote attacker to cause an unexpected reload of the Network Processing Unit (NPU) process. More Information: CSCva84552. Known Affected Releases: 20.0.0 21.0.0 21.0.M0.64702. Known Fixed Releases: 21.0.0 21.0.0.65256 21.0.M0.64970 21.0.V0.65150 21.1.A0.64973 21.1.PP0.65270 21.1.R0.65130 21.1.R0.65135 21.1.VC0.65203.

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 IPv6 packet fragment reassembly in StarOS on Cisco ASR 5000 Series Switches allows an unauthenticated remote attacker to send specially crafted IPv6 packet fragments that cause an unexpected reload of the Network Processing Unit (NPU) process, resulting in denial of service.

MitigationApply the appropriate fixed StarOS release (21.0.0.65256, 21.0.M0.64970, 21.0.V0.65150, 21.1.A0.64973, 21.1.PP0.65270, 21.1.R0.65135, or 21.1.VC0.65203) or later. Until patched, consider filtering IPv6 traffic at network boundaries to block potentially malicious fragment packets.

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
Asr 5000 Series SoftwareApplication
Affected:= 20.0.0= 21.0.0= 21.0.m0.64702

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:3.0/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 device model
    Verify the hardware is a Cisco ASR 5000 Series Switch by checking the device inventory or running 'show hardware' command
    Affected if Device is not an ASR 5000 Series Switch (different models are not affected)
  2. Check StarOS version
    Run 'show version' or 'show software' command to display the installed StarOS version
    Affected if Version is 20.0.0, 21.0.0, or 21.0.m0.64702 specifically (these are the exact versions listed as affected)
  3. Verify IPv6 is enabled
    Check if IPv6 feature or service is enabled on the system using 'show ip interface' or 'show configuration | include ipv6'
    Affected if IPv6 is disabled - the vulnerability only affects IPv6 packet fragment reassembly processing
  4. Confirm IPv6 traffic processing
    Check if the device is configured to process IPv6 traffic by reviewing active interfaces with 'show ip interface' or checking IPv6 routing status
    Affected if Device has no IPv6 interfaces configured or IPv6 routing is disabled - no attack surface exists
  5. Compare version to affected ranges
    If running a different version number than the three listed, compare it to the affected versions: 20.0.0, 21.0.0, 21.0.m0.64702
    Affected if Version matches exactly one of the three affected versions listed

Device is affected only if it is a Cisco ASR 5000 Series running StarOS version 20.0.0, 21.0.0, or 21.0.m0.64702 with IPv6 enabled and configured to process IPv6 traffic.

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 appropriate fixed StarOS release (21.0.0.65256, 21.0.M0.64970, 21.0.V0.65150, 21.1.A0.64973, 21.1.PP0.65270, 21.1.R0.65135, or 21.1.VC0.65203) or later. Until patched, consider filtering IPv6 traffic at network boundaries to block potentially malicious fragment packets.

Fix this in Asr 5000 Series Software Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,840
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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-2016-6467 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