Ios XrOperating system · Cisco
CVE-2015-6301
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 · uneditedThe 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 CSCun72171.
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 · moderate confidenceThe DHCPv6 server implementation in Cisco IOS on ASR 9000 routers running software version 5.2.0 Base contains a vulnerability that can be exploited by remote attackers sending specially crafted DHCPv6 packets. Successful exploitation causes a process reset, resulting in denial of service. The attack does not require authentication.
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
= 5.2.0_base
Asr 9001Hardware / appliance
all versions
Asr 9006Hardware / appliance
all versions
Asr 9010Hardware / appliance
all versions
Asr 9904Hardware / appliance
all versions
Asr 9912Hardware / appliance
all versions
Asr 9922Hardware / appliance
all versionsCVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify the router modelRun 'show platform' or check hardware inventory with 'show inventory' to confirm the device is an ASR 9000 series router (ASR 9001, 9006, 9010, 9904, 9912, or 9922)Affected if The device model matches any of the affected ASR 9000 series models listed in the CVE
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Check the IOS XR versionRun 'show version' to display the running Cisco IOS XR versionAffected if The version is 5.2.0_base or if the device is an ASR 9001/9006/9010/9904/9912/9922 running any version (since these models list 'all versions' as affected)
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Verify DHCPv6 server configurationRun 'show running-config | include dhcpv6' and 'show dhcpv6 server' to check if DHCPv6 server is enabled and configured on any interfaceAffected if DHCPv6 server feature is configured and active on the device
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Check interface DHCPv6 bindingsRun 'show dhcpv6 server binding' to display active DHCPv6 client bindingsAffected if There are active DHCPv6 server bindings, indicating the feature is in use and potentially exposed to network traffic
A user is affected if they operate an ASR 9000 series router (specifically 9001, 9006, 9010, 9904, 9912, or 9922) running any IOS version with DHCPv6 server feature enabled and reachable by untrusted DHCPv6 traffic.
Generated from the published advisory. Verify against your own configuration.
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 dataApply the Cisco IOS update that addresses this vulnerability; in the interim, consider filtering or rate-limiting inbound DHCPv6 traffic from untrusted sources at network boundaries.
Fix this in Ios Xr
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-6301 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2015-6301 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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