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Mobility Express SoftwareOperating system · Cisco

CVE-2023-20251

MEDIUM · 5.3 CVSS v3.1 Published 2023-09-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
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 memory buffer of Cisco Wireless LAN Controller (WLC) AireOS Software could allow an unauthenticated, adjacent attacker to cause memory leaks that could eventually lead to a device reboot. This vulnerability is due to memory leaks caused by multiple clients connecting under specific conditions. An attacker could exploit this vulnerability by causing multiple wireless clients to attempt to connect to an access point (AP) on an affected device. A successful exploit could allow the attacker to cause the affected device to reboot after a significant amount of time, resulting in a denial of service (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 confidence

A vulnerability in Cisco Wireless LAN Controller (WLC) AireOS Software allows an unauthenticated, adjacent attacker to cause memory leaks by triggering multiple wireless clients to connect to an access point on an affected device. The memory leaks accumulate over time under specific client connection conditions and can eventually cause the affected device to reboot, resulting in denial of service.

MitigationApply the Cisco-provided software patch for AireOS when available; until then, monitor WLC memory utilization and consider network segmentation to limit adjacent attack surface.

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
Mobility Express SoftwareOperating system
Affected:all versions

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
Adjacent
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/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. Identify device type and software version
    Use the 'show version' command or check the system GUI to confirm the device is running Cisco Wireless LAN Controller or Cisco Mobility Express software. Record the exact software version string.
    Affected if The device runs any version of Cisco Mobility Express software (all versions are affected).
  2. Confirm wireless access point functionality is enabled
    Check if the device has access points (APs) joined and broadcasting SSIDs. Use 'show ap config' or 'show wlan summary' commands to list active wireless networks and connected APs.
    Affected if Access points are joined and wireless clients can connect to them - the vulnerability is triggered by client associations to an AP.
  3. Monitor memory utilization
    Execute 'show processes memory' or check the controller's monitoring interface for memory usage statistics. Record the used and available memory, focusing on the system memory pool.
    Affected if Memory usage shows continuous growth or abnormally high utilization over time without returning to baseline levels.
  4. Check for device instability or reboots
    Review system logs, crash logs, or use 'show logging' to identify any unexpected reloads or system resets. Check 'show boot' for last reload reason.
    Affected if The device has experienced unexplained reloads or the last reload reason indicates a memory exhaustion condition.

A user is affected if they run any version of Cisco Mobility Express software with active access points that allow wireless client connections, and they observe abnormally high memory consumption or unexpected device reboots.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco-provided software patch for AireOS when available; until then, monitor WLC memory utilization and consider network segmentation to limit adjacent attack surface.

Fix this in Mobility Express Software Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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Scan for this in your stack

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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-2023-20251 in production — separate from our analysis above.

No notes yet

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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