Ios XeOperating system · Cisco
CVE-2021-1565
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 · uneditedMultiple vulnerabilities in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE Software for Cisco Catalyst 9000 Family Wireless Controllers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. These vulnerabilities are due to insufficient validation of CAPWAP packets. An attacker could exploit the vulnerabilities by sending a malformed CAPWAP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition.
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 confidenceMultiple vulnerabilities in the CAPWAP (Control and Provisioning of Wireless Access Points) protocol processing in Cisco IOS XE Software for Cisco Catalyst 9000 Family Wireless Controllers allow an unauthenticated, remote attacker to cause device crash and reload by sending malformed CAPWAP packets. The vulnerabilities stem from insufficient validation of CAPWAP packet data.
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
= 3.15.1xbs= 3.15.2xbs= 17.3.1= 17.3.2= 17.4.1= 17.5.1
Embedded Wireless ControllerApplication
all versions
Catalyst 9800 FirmwareOperating system
= 17.3= 17.5.1CVSS 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
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
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 device modelRun 'show version' or 'show inventory' to confirm the hardware modelAffected if Device is a Cisco Catalyst 9000 Family Wireless Controller, Cisco Embedded Wireless Controller, or Cisco Catalyst 9800 Series Wireless Controller
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Check the IOS XE firmware versionRun 'show version' and locate the Cisco IOS XE version stringAffected if Version is 3.15.1xbs, 3.15.2xbs, 17.3.1, 17.3.2, 17.4.1, 17.5.1, 17.3, or any version on Cisco Embedded Wireless Controller (all versions affected)
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Verify CAPWAP protocol is activeRun 'show capwap summary' or 'show wireless capwap summary' to confirm CAPWAP process is runningAffected if CAPWAP is enabled and the device is accepting CAPWAP connections (wireless controller functionality is active)
You are affected if you run a Cisco Catalyst 9000 Wireless Controller, Embedded Wireless Controller, or Catalyst 9800 with an affected IOS XE version and CAPWAP is enabled.
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 vendor-supplied Cisco IOS XE software updates for the Catalyst 9000 Family Wireless Controllers to patch the CAPWAP validation vulnerabilities.
Fix this in Ios Xe
Scoped from the published advisory
- Consultation4.0 h
- Implementation3.0 h
- Testing2.0 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 $3,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1565 — 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-2021-1565 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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