5520 Wireless Lan Controller FirmwareOperating system · Cisco
CVE-2019-15262
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 Secure Shell (SSH) session management for Cisco Wireless LAN Controller (WLC) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability exists because the SSH process is not properly deleted when an SSH connection to the device is disconnected. An attacker could exploit this vulnerability by repeatedly opening SSH connections to an affected device. A successful exploit could allow the attacker to exhaust system resources by initiating multiple SSH connections to the device that are not effectively terminated, which could result 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 confidenceA vulnerability in Cisco Wireless LAN Controller software allows SSH processes to remain active after disconnection. Attackers can repeatedly open SSH connections without proper cleanup, exhausting device resources and causing denial of service.
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
5520 Wireless Lan Controller FirmwareOperating system
<= 8.5.140.0
5508 Wireless Lan Controller FirmwareOperating system
<= 8.5.140.0CVSS 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
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify the Wireless LAN Controller modelLog into the controller CLI and run 'show inventory' or check the physical device label to confirm the model numberAffected if Model is NOT Cisco 5520 or Cisco 5508 (these are the only affected models)
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Check the installed firmware versionLog into the controller CLI and run 'show version' to display the firmware versionAffected if Firmware version is 8.5.140.0 or lower (any version <= 8.5.140.0 is affected)
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Verify SSH management access is enabledRun 'show ssh' or 'show ip ssh' in the controller CLI to check if SSH is enabled and which IP addresses are allowedAffected if SSH is enabled and accessible from untrusted networks (exposure increases likelihood of exploitation)
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Check for abnormal SSH connection patternsRun 'show ssh session' or 'show connections' to view active and recent SSH connections, looking for excessive数量的连接或卡住的会话Affected if Multiple stale SSH sessions exist or connection counts are unusually high without legitimate cause
You are affected if you are running a Cisco 5520 or 5508 Wireless LAN Controller with firmware version 8.5.140.0 or lower and SSH management is enabled and accessible
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 dataImplement network-level controls such as ACLs or firewall rules restricting SSH management access to trusted IPs, and monitor for abnormal SSH connection patterns indicating resource exhaustion.
Fix this in 5520 Wireless Lan Controller Firmware
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 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 $3,168.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-15262 — 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-2019-15262 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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