dbcve.org
Asr 5000 Series SoftwareApplication · Cisco

CVE-2016-6466

HIGH · 7.5 CVSS v3.0 Published 2016-11-19
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 IPsec component of StarOS for Cisco ASR 5000 Series routers could allow an unauthenticated, remote attacker to terminate all active IPsec VPN tunnels and prevent new tunnels from establishing, resulting in a denial of service (DoS) condition. This vulnerability affects the following Cisco products: Cisco ASR 5000/5500 Series routers, Cisco Virtualized Packet Core (VPC). More Information: CSCva13631. Known Affected Releases: 20.0.0 20.1.0 20.2.0 20.2.3 20.2.v1 21.0.0 21.0.M0.64246. Known Fixed Releases: 20.2.3 20.2.3.65026 20.2.a4.65307 20.2.v1 20.2.v1.65353 20.3.M0.65037 20.3.T0.65043 21.0.0 21.0.0.65256 21.0.M0.64595 21.0.M0.64860 21.0.M0.65140 21.0.V0.65052 21.0.V0.65150 21.0.V0.65366 21.0.VC0.64639 21.1.A0.64861 21.1.A0.65145 21.1.PP0.65270 21.1.R0.65130 21.1.R0.65135 21.1.R0.65154 21.1.VC0.64898 21.1.VC0.65203 21.2.A0.65147.

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 IPsec component of StarOS allows an unauthenticated, remote attacker to terminate all active IPsec VPN tunnels and prevent new tunnel establishment, causing a denial of service. The attack requires no authentication and targets the IPsec VPN functionality on affected Cisco ASR 5000/5500 Series routers and Virtualized Packet Core deployments.

MitigationApply the appropriate fixed StarOS release from the known fixed releases list after thorough testing in a non-production environment, and schedule a maintenance window to minimize impact on active VPN tunnels.

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= 20.0.2.3= 20.0.2.v1
Virtualized Packet CoreApplication
Affected:= 20.0_base

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 the product platform
    Determine if the device is a Cisco ASR 5000/5500 Series router or a Virtualized Packet Core deployment. Use 'show platform' or check the physical chassis/labels for ASR hardware, or verify the virtualization environment for VPC.
    Affected if The device is not an ASR 5000/5500 Series router or Virtualized Packet Core - this CVE does not apply.
  2. Check the StarOS version
    Execute 'show version' or 'show release' from the CLI to retrieve the installed StarOS software version.
    Affected if The version matches exactly 20.0.0, 20.0.2.3, 20.0.2.v1, or 20.0_base - these are the affected versions.
  3. Verify IPsec VPN is configured
    Execute 'show ipsec' or 'show vpn' to check if IPsec VPN tunnels are configured and active on the system.
    Affected if No IPsec VPN tunnels are configured - the vulnerability targets active IPsec VPN functionality, so an unconfigured IPsec feature would not be exploitable.
  4. Check for existing IPsec tunnel status
    Execute 'show ipsec sa' or 'show crypto ipsec sa' to display active IPsec security associations and tunnel count.
    Affected if Active IPsec tunnels exist - the attacker can terminate these and prevent new tunnel establishment, causing denial of service.

The environment is affected if the device is an ASR 5000/5500 Series router or Virtualized Packet Core running StarOS version 20.0.0, 20.0.2.3, 20.0.2.v1, or 20.0_base with IPsec VPN functionality enabled or configured.

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 from the known fixed releases list after thorough testing in a non-production environment, and schedule a maintenance window to minimize impact on active VPN tunnels.

Fix this in Asr 5000 Series Software Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,800
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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-2016-6466 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