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Ios XeOperating system · Cisco

CVE-2023-20100

MEDIUM · 6.8 CVSS v3.1 Published 2023-03-23
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
77/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
A vulnerability in the access point (AP) joining process of the Control and Provisioning of Wireless Access Points (CAPWAP) protocol of Cisco IOS XE Software for Wireless LAN Controllers (WLCs) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to a logic error that occurs when certain conditions are met during the AP joining process. An attacker could exploit this vulnerability by adding an AP that is under their control to the network. The attacker then must ensure that the AP successfully joins an affected wireless controller under certain conditions. Additionally, the attacker would need the ability to restart a valid AP that was previously connected to the controller. A successful exploit could allow the attacker to cause the affected device to restart unexpectedly, 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 · moderate confidence

A logic error in the CAPWAP protocol's access point joining process in Cisco IOS XE Wireless LAN Controllers allows an unauthenticated remote attacker to cause device restarts. Exploitation requires the attacker to add a malicious AP to the network that successfully joins the controller under specific conditions, combined with the ability to restart a previously connected legitimate AP.

MitigationApply the Cisco IOS XE software update addressing CVE-2023-20100. Until patched, limit AP management permissions and monitor for unauthorized AP additions to the wireless 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
Affected:= 17.10.1

CVSS 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
High
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify IOS XE version
    Run 'show version' and look for the software version number in the output. Compare the version string to 17.10.1.
    Affected if The installed IOS XE version is exactly 17.10.1
  2. Confirm Wireless LAN Controller is active
    Run 'show wireless summary' or 'show controllers' to verify the Wireless LAN Controller feature is enabled and running.
    Affected if Wireless LAN Controller is enabled and running on the device
  3. Check CAPWAP protocol status
    Run 'show capwap status' or 'show capwap summary' to confirm CAPWAP is configured and active for access point communications.
    Affected if CAPWAP protocol is active and accepting AP connections
  4. Review AP join events for unauthorized APs
    Run 'show ap join summary' or check AP management logs to list all access points that have successfully joined the controller. Look for unknown or unexpected AP MAC addresses.
    Affected if There are unauthorized or unexpected APs listed in the join summary
  5. Check for recent device restarts
    Run 'show reload' or review system logs for unexpected reload events. Look for restarts that were not initiated by an administrator.
    Affected if There are unexplained device restarts or reloads

The environment is affected if the device runs Cisco IOS XE version 17.10.1 with the Wireless LAN Controller feature enabled and CAPWAP active, and there are signs of unauthorized APs or unexplained device restarts.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco IOS XE software update addressing CVE-2023-20100. Until patched, limit AP management permissions and monitor for unauthorized AP additions to the wireless network.

Recommended fix Moderate confidence

Obtain the specific fixed release from Cisco Security Advisory (typically a later maintenance release such as 17.10.2 or later)

  1. 1. Identify the current Cisco IOS XE Wireless LAN Controller version using 'show version' command
  2. 2. Access the Cisco Security Advisory at sec.cloudapps.cisco.com for CVE-2023-20100 to obtain the specific fixed release number
  3. 3. Plan an upgrade window as the controller will need to be reloaded
  4. 4. Download the fixed IOS XE software version from Cisco's software download center
  5. 5. Back up the current WLC configuration
  6. 6. Upload the new IOS XE image to the WLC
  7. 7. Configure the new boot variable to point to the fixed image
  8. 8. Reload the WLC to apply the fixed version
Caveat Standard IOS XE upgrade precautions apply - ensure configuration compatibility and plan for controller downtime during reload

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-20100 in production — separate from our analysis above.

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What this is

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.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data