Asr 5000 Series SoftwareApplication · Cisco
CVE-2015-6256
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 · uneditedCisco ASR 5000 devices with software 19.0.M0.60828 allow remote attackers to cause a denial of service (OSPF process restart) via crafted length fields in headers of OSPF packets, aka Bug ID CSCuv62820.
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 confidenceDenial of service vulnerability in Cisco ASR 5000 devices allows remote attackers to restart the OSPF process by sending OSPF packets with crafted length fields in packet headers, causing service disruption.
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
Asr 5000 Series SoftwareApplication
= 19.0.m0.60828CVSS 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 installed software versionExecute 'show version' or 'show software' command on the Cisco ASR 5000 CLI to retrieve the running software versionAffected if The displayed version number is exactly 19.0.m0.60828
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Confirm OSPF process is activeExecute 'show ospf' or 'show ospf neighbor' command to verify OSPF is enabled and runningAffected if OSPF process is up and actively participating in routing
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Verify OSPF packet receptionExecute 'show ospf interface' to confirm OSPF is bound to any interface and listening for OSPF packetsAffected if OSPF is bound to one or more physical or logical interfaces accepting OSPF packets
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Check OSPF authentication configurationExecute 'show ospf interface' and look for 'Message-Digest' or 'MD5' authentication keywords in the interface OSPF configurationAffected if OSSPF authentication is not configured (showing 'null' or no authentication method) and interfaces are accessible to untrusted networks
You are affected if your Cisco ASR 5000 runs version 19.0.m0.60828, OSPF is enabled and reachable from untrusted network segments, and OSPF MD5 authentication is not configured.
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 dataUpgrade Cisco ASR 5000 software to a patched version beyond 19.0.M0.60828. Additionally, implement OSPF MD5 authentication and network filtering to block unauthorized OSPF packets from untrusted sources.
Fix this in Asr 5000 Series Software
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-6256 — 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-2015-6256 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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- 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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