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iOSOperating system · Cisco

CVE-2017-12211

MEDIUM · 5.3 CVSS v3.0 Published 2017-09-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable 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 IPv6 Simple Network Management Protocol (SNMP) code of Cisco IOS and Cisco IOS XE Software could allow an authenticated, remote attacker to cause high CPU usage or a reload of the device. The vulnerability is due to IPv6 sub block corruption. An attacker could exploit this vulnerability by polling the affected device IPv6 information. An exploit could allow the attacker to trigger high CPU usage or a reload of the device. Known Affected Releases: Denali-16.3.1. Cisco Bug IDs: CSCvb14640.

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 IPv6 SNMP code of Cisco IOS and IOS XE Software allows an authenticated, remote attacker to cause high CPU usage or device reload due to IPv6 sub block corruption. Exploitation requires polling the affected device for IPv6 information using valid SNMP credentials.

MitigationApply the Cisco firmware fix from the relevant vendor advisories for CSCvb14640 and consider restricting SNMP access to authorized management stations or disabling IPv6 SNMP if not required.

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:= 3.16.1
Ios XeOperating system
Affected:= 3.16.1

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

CVSS:3.0/AV:N/AC:H/PR:L/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 Cisco device OS type
    Run 'show version' or 'show inventory' to confirm the device runs Cisco IOS or IOS XE software
    Affected if Device does not run Cisco IOS or IOS XE - the vulnerability only affects these platforms
  2. Check the IOS/IOS XE version
    Run 'show version' and locate the software version string (for example, 3.16.1 or similar)
    Affected if Version matches or falls within the affected version range around 3.16.1 - compare your installed version to the affected ranges
  3. Verify SNMP is configured
    Run 'show snmp' or 'show running-config | include snmp' to check if SNMP is enabled
    Affected if SNMP is not configured - exploitation requires valid SNMP credentials to poll the device
  4. Confirm IPv6 SNMP is active
    Run 'show snmp mib ifmib ifindex' and check for IPv6 MIB objects, or review 'show snmp' output for IPv6-related activity
    Affected if IPv6 SNMP is not being used - the vulnerability exists specifically in the IPv6 SNMP code path

The device is affected if it runs Cisco IOS or IOS XE version 3.16.1 (or affected range), has SNMP configured, and IPv6 SNMP queries are possible.

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 Cisco firmware fix from the relevant vendor advisories for CSCvb14640 and consider restricting SNMP access to authorized management stations or disabling IPv6 SNMP if not required.

Fix this in iOS Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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Scan for this in your stack

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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-2017-12211 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