Ios XeOperating system · Cisco
CVE-2025-20221
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 IOS XE SD-WAN Software could allow an unauthenticated, remote attacker to bypass Layer 3 and Layer 4 traffic filters. This vulnerability is due to improper traffic filtering conditions on an affected device. An attacker could exploit this vulnerability by sending a crafted packet to the affected device. A successful exploit could allow the attacker to bypass the Layer 3 and Layer 4 traffic filters and inject a crafted 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 confidenceA critical vulnerability in Cisco IOS XE SD-WAN Software allows unauthenticated remote attackers to bypass Layer 3 and Layer 4 packet filtering controls. The flaw stems from improper traffic filtering conditions that can be exploited by sending crafted packets to the affected device, enabling injection of malicious traffic into the network despite configured filters.
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
= 16.12.13= 17.1.1= 17.1.1s= 17.1.1t= 17.1.3= 17.2.1= 17.2.1a= 17.2.1r= 17.2.1v= 17.2.2= 17.2.3= 17.3.1CVSS 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
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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 device platform and software typeRun 'show version' or 'show sdwan software' command to confirm the device is running Cisco IOS XE with SD-WAN capabilityAffected if Device is not running Cisco IOS XE SD-WAN software (not applicable)
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Determine installed IOS XE versionExecute 'show version' and locate the IOS XE release line (typically shows as 'Version 17.X.Y' or similar)Affected if Cannot determine version from output
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Compare version against affected listMatch the installed version exactly to the following list: 16.12.13, 17.1.1, 17.1.1s, 17.1.1t, 17.1.3, 17.2.1, 17.2.1a, 17.2.1r, 17.2.1v, 17.2.2, 17.2.3, 17.3.1Affected if Installed version matches one of these exact versions
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Verify SD-WAN feature is operationalRun 'show sdwan control connections' or 'show sdwan interface' to confirm SD-WAN features are actively enabled on the deviceAffected if SD-WAN features are enabled and running
Device is affected if it runs Cisco IOS XE SD-WAN software AND the installed version exactly matches one of these versions: 16.12.13, 17.1.1, 17.1.1s, 17.1.1t, 17.1.3, 17.2.1, 17.2.1a, 17.2.1r, 17.2.1v, 17.2.2, 17.2.3, 17.3.1 AND SD-WAN functionality is actively in use.
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 Cisco's available patches for IOS XE SD-WAN software; review and verify existing Layer 3 and Layer 4 filter configurations after patching to ensure proper enforcement.
Fix this in Ios Xe
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-20221 — 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-2025-20221 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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