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iOSOperating system · Cisco

CVE-2016-1459

MEDIUM · 5.3 CVSS v3.0 Published 2016-07-17
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
Cisco IOS 12.4 and 15.0 through 15.5 and IOS XE 3.13 through 3.17 allow remote authenticated users to cause a denial of service (device reload) via crafted attributes in a BGP message, aka Bug ID CSCuz21061.

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 denial-of-service vulnerability in Cisco IOS and IOS XE where remote authenticated users can send specially crafted BGP (Border Gateway Protocol) messages containing malicious attributes, causing the affected device to reload. The vulnerability exists due to improper validation of BGP attribute fields.

MitigationApply the relevant Cisco software update/patch for the specific IOS/IOS XE version in use. For Cisco IOS, this is addressed in fixes for Bug ID CSCuz21061. As a temporary measure, consider implementing BGP route filtering and prefix validation to limit which BGP peers can send traffic.

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:= 12.4\(4\)xc7= 12.4\(15\)t17= 12.4\(19a\)= 12.4\(22\)yb2= 12.4\(24\)gc4= 12.4\(24\)gc5= 15.0\(1\)ex= 15.0\(1\)m= 15.0\(1\)m9= 15.0\(1\)m10= 15.0\(1\)s= 15.0\(1\)sy
Ios XeOperating system
Affected:= 3.13.2s= 3.13.3s= 3.13.4s= 3.13.5s= 3.14.0s= 3.14.1s= 3.14.2s= 3.14.3s= 3.14.4s= 3.15.1cs= 3.15.2s= 3.15.3s

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 software version
    Run 'show version' on the device CLI to obtain the IOS or IOS XE version string
    Affected if The version matches one of the listed affected versions: 12.4(4)xc7, 12.4(15)t17, 12.4(19a), 12.4(22)yb2, 12.4(24)gc4, 12.4(24)gc5, 15.0(1)ex, 15.0(1)m, 15.0(1)m9, 15.0(1)m10, 15.0(1)s, 15.0(1)sy for IOS, or 3.13.2s, 3.13.3s, 3.13.4s, 3.13.5s, 3.14.0s, 3.14.1s, 3.14.2s, 3.14.3s, 3.14.4s, 3.15.1cs, 3
  2. Verify BGP is enabled on the device
    Run 'show ip bgp summary' or 'show bgp all summary' to check if BGP process is running
    Affected if BGP is active and the command returns neighbor information, indicating the router is participating in BGP
  3. Confirm BGP peers are configured
    Run 'show ip bgp neighbors' to list configured BGP peers
    Affected if One or more BGP peers exist, meaning remote authenticated users could potentially send malicious BGP messages
  4. Check for BGP route filtering
    Run 'show running-config | include bgp' and review any route-map, prefix-list, or AS-path access-lists applied to BGP neighbors
    Affected if No route filtering, prefix validation, or neighbor authentication controls are configured, exposing the device to unauthenticated or unvalidated BGP updates

The device is affected if it runs one of the listed Cisco IOS or IOS XE versions AND has BGP enabled with configured peers, regardless of filtering controls in place.

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 relevant Cisco software update/patch for the specific IOS/IOS XE version in use. For Cisco IOS, this is addressed in fixes for Bug ID CSCuz21061. As a temporary measure, consider implementing BGP route filtering and prefix validation to limit which BGP peers can send traffic.

Fix this in iOS Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2016-1459 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