Nx OsOperating system · Cisco
CVE-2020-10136
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 · uneditedIP-in-IP protocol specifies IP Encapsulation within IP standard (RFC 2003, STD 1) that decapsulate and route IP-in-IP traffic is vulnerable to spoofing, access-control bypass and other unexpected behavior due to the lack of validation to verify network packets before decapsulation and routing.
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 IP-in-IP protocol (RFC 2003) implementation lacks validation of network packets before decapsulation and routing. This allows attackers to craft malicious encapsulated packets that bypass access controls or spoof traffic by exploiting the absence of integrity and source verification checks.
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
Nx OsOperating system
= 5.2\(1\)sk3\(1.1\)= 5.2\(1\)sk3\(2.1\)= 5.2\(1\)sk3\(2.1a\)= 5.2\(1\)sk3\(2.2\)= 5.2\(1\)sk3\(2.2b\)= 5.2\(1\)sm1\(5.1\)= 5.2\(1\)sm1\(5.2\)= 5.2\(1\)sm1\(5.2a\)= 5.2\(1\)sm1\(5.2b\)= 5.2\(1\)sm1\(5.2c\)= 5.2\(1\)sm3\(1.1\)= 5.2\(1\)sm3\(1.1a\)
Ucs ManagerApplication
= 3.2\(3n\)a
Unified Computing SystemApplication
all versions< 8.1.0.1< 3.00.11.08< 6.0.1.67CVSS 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
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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 product and versionQuery the system or device for its exact software/firmware version. For Cisco NX-OS use 'show version', for Cisco UCS Manager use 'show version', for Digi Saros use system info, for HP X3220nr check firmware version via diagnostic interface, for Treck TCP/IP check library version via application or firmware manifestAffected if The version matches one listed in the affected version ranges (specific Cisco versions, Digi Saros < 8.1.0.1, HP X3220nr < 3.00.11.08, Treck TCP/IP < 6.0.1.67) or for Cisco UCS 3.2(3n)a or Cisco Unified Computing System all versions
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Confirm IP-in-IP protocol is enabledCheck the network configuration for active IP-in-IP tunnel interfaces or protocols. On Cisco devices look for 'ip ipip' tunnel interfaces or 'tunnel mode ipip'. On Digi Saros check tunnel settings. On embedded systems check if IPIP encapsulation is loaded or configuredAffected if IP-in-IP tunneling or encapsulation is actively configured or the IPIP protocol module is loaded
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Verify IP-in-IP packet processing is exposedInspect whether the device is processing external IP-in-IP traffic or acting as a tunnel endpoint accessible from untrusted networks. Check access lists, firewall rules, or interface configurations that permit IP protocol 4 (IP-in-IP) trafficAffected if The device accepts or processes IP-in-IP packets from network interfaces connected to untrusted networks
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Review decapsulation behaviorExamine if the system decapsulates and routes IP-in-IP packets without additional integrity or source validation beyond standard IP checks. Check if there are any ingress filters or anti-spoofing measures applied specifically to encapsulated trafficAffected if The system decapsulates IP-in-IP packets and routes them without verifying the inner source address or checking packet integrity
A user is affected if their device runs an affected version AND has IP-in-IP protocol enabled or processes IP-in-IP traffic from external sources.
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 data3.00.11.086.0.1.678.1.0.1
Implement strict validation of IP-in-IP packet headers and addresses before decapsulation, and disable or filter IP-in-IP traffic at network boundaries unless explicitly required.
Fix this in Nx Os
Scoped from the published advisory
- Consultation4.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,960.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-10136 — 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-2020-10136 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
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