Ios XeOperating system · Cisco
CVE-2020-3444
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 · uneditedA vulnerability in the packet filtering features of Cisco SD-WAN Software could allow an unauthenticated, remote attacker to bypass L3 and L4 traffic filters. The vulnerability is due to improper traffic filtering conditions on an affected device. An attacker could exploit this vulnerability by crafting a malicious TCP packet with specific characteristics and sending it to a targeted device. A successful exploit could allow the attacker to bypass the L3 and L4 traffic filters and inject an arbitrary packet into the network.
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 confidenceCisco SD-WAN contains a packet filtering bypass vulnerability where improper traffic filtering conditions allow a remote attacker to craft malicious TCP packets with specific characteristics that bypass L3 and L4 layer filters, enabling injection of arbitrary packets into the network.
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 XeOperating system
<= 16.12.2r>= 17.2, <= 17.2.1CVSS 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
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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 IOS XE versionRun the 'show version' command on the SD-WAN device to obtain the Cisco IOS XE software version numberAffected if The installed version is 16.12.2r or lower, or falls between 17.2 and 17.2.1 inclusive
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Confirm SD-WAN is enabledRun 'show sdwan version' or 'show sdwan running-config' to verify the SD-WAN feature is actively running on the deviceAffected if SD-WAN software features are enabled and the device is functioning as a SD-WAN edge node
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Locate the L3/L4 filtering configurationExecute 'show sdwan policy lists' to view the configured packet filtering policy lists, or inspect the SD-WAN CLI configuration for filter entries under the policy configuration modeAffected if L3 and L4 packet filtering rules are defined in the SD-WAN configuration and applied to data traffic
The environment is affected if the device runs a vulnerable Cisco IOS XE SD-WAN version within the stated ranges and has SD-WAN packet filtering actively 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 dataApply the Cisco patch/update for this vulnerability; until patched, implement additional network segmentation and monitor for suspicious traffic patterns targeting SD-WAN edge devices.
Fix this in Ios Xe
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 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 $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3444 — 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-2020-3444 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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