Ios XrOperating system · Cisco
CVE-2014-3271
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 implementation in Cisco IOS XR allows remote attackers to cause a denial of service (device crash) via a malformed packet, aka Bug IDs CSCum85558, CSCum20949, CSCul61849, and CSCul71149.
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 confidenceA denial of service vulnerability exists in the DHCPv6 implementation of Cisco IOS XR. Remote attackers can send malformed DHCPv6 packets to cause the affected device to crash. The vulnerability is network-exploitable and requires no 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
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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Confirm the device runs Cisco IOS XRIdentify the device operating system using 'show version' or 'cat /proc/version' if accessible, or check device inventory/management interfaceAffected if The device is running any version of Cisco IOS XR software
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Check the IOS XR versionExecute 'show version' on the device to obtain the installed software versionAffected if Any Cisco IOS XR version is installed, as all versions are affected according to the CVE
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Determine if DHCPv6 is enabledRun 'show running-config | include dhcpv6' or 'show dhcpv6' commands to check for DHCPv6 configuration on the deviceAffected if DHCPv6 is configured or active on the device - the vulnerability exists in the DHCPv6 implementation
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Verify IPv6 network exposureCheck interfaces with 'show ipv6 interface brief' to determine if IPv6 is enabled and assess whether the device is reachable from untrusted networksAffected if The device has IPv6 connectivity and is accessible from network segments where untrusted DHCPv6 packets could be received
A Cisco IOS XR device with DHCPv6 enabled and IPv6 network exposure is vulnerable to denial of service via malformed DHCPv6 packets.
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 relevant Cisco IOS XR software updates/patches corresponding to Bug IDs CSCum85558, CSCum20949, CSCul61849, and CSCul71149. As an interim measure, consider filtering or rate-limiting DHCPv6 traffic at network edges using ACLs.
Fix this in Ios Xr
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2014-3271 — 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-2014-3271 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
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