dbcve.org
Ios XrOperating system · Cisco

CVE-2015-6297

MEDIUM · 5.0 CVSS v2.0 Published 2015-09-18
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 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
The DHCPv6 server in Cisco IOS on ASR 9000 devices with software 5.2.0 Base allows remote attackers to cause a denial of service (process reset) via crafted packets, aka Bug ID CSCun36525.

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

The DHCPv6 server in Cisco IOS on ASR 9000 routers with software version 5.2.0 Base contains a vulnerability where processing specifically crafted DHCPv6 packets triggers a process reset, causing denial of service. This is a remote, network-based attack requiring no authentication.

MitigationUpgrade to a Cisco IOS software version that addresses this vulnerability. As an interim measure, consider filtering or rate-limiting DHCPv6 traffic at network edges using ACLs, or disable the DHCPv6 server feature 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
Ios XrOperating system
Affected:= 5.2.0_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
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial

AV:N/AC:L/Au:N/C:N/I:N/A:P

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
    Run 'show platform' or check hardware inventory to confirm the device is an ASR 9000 series router
    Affected if Device is not an ASR 9000 router - not affected by this specific CVE
  2. Check IOS XR version
    Run 'show version' and look for the software version string. Verify it matches exactly '5.2.0 Base'
    Affected if Version is not 5.2.0 Base - not affected by this CVE (only this specific version is listed)
  3. Confirm DHCPv6 server is enabled
    Run 'show dhcpv6 server' or 'show running-config | include dhcpv6' to check if the DHCPv6 server feature is configured
    Affected if DHCPv6 server is not enabled - the vulnerability cannot be triggered even on affected version

You are affected if you have an ASR 9000 router running exactly Cisco IOS XR 5.2.0 Base with the DHCPv6 server feature enabled and the device is network-accessible to malicious DHCPv6 packets.

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

Upgrade to a Cisco IOS software version that addresses this vulnerability. As an interim measure, consider filtering or rate-limiting DHCPv6 traffic at network edges using ACLs, or disable the DHCPv6 server feature if not required.

Fix this in Ios Xr Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2015-6297 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