dbcve.org
2000 Wireless Lan ControllerHardware / appliance · Cisco

CVE-2013-1235

MEDIUM · 5.0 CVSS v2.0 Published 2013-05-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
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
Cisco Wireless LAN Controller (WLC) devices do not properly address the resource consumption of terminated TELNET sessions, which allows remote attackers to cause a denial of service (TELNET outage) by making many TELNET connections and improperly ending these connections, aka Bug ID CSCug35507.

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

Cisco Wireless LAN Controller devices fail to properly release resources when TELNET sessions are terminated improperly. Remote attackers can repeatedly initiate TELNET connections and abort them without proper logout, causing resource exhaustion that leads to a TELNET service outage.

MitigationDisable TELNET access on the WLC and enforce SSH for management access. If TELNET is required, restrict it to specific management networks and implement connection rate limiting.

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
2000 Wireless Lan ControllerHardware / appliance
Affected:all versions
2100 Wireless Lan ControllerHardware / appliance
Affected:all versions
2106 Wireless Lan ControllerHardware / appliance
Affected:all versions
2112 Wireless Lan ControllerHardware / appliance
Affected:all versions
2125 Wireless Lan ControllerHardware / appliance
Affected:all versions
2500 Wireless Lan ControllerHardware / appliance
Affected:all versions
2504 Wireless Lan ControllerHardware / appliance
Affected:all versions
4100 Wireless Lan ControllerHardware / appliance
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
Network
Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial

AV:N/AC:L/Au:N/C:N/I:N/A:P

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. Confirm device model is affected
    Identify the Cisco Wireless LAN Controller model number using 'show inventory' or the device label. Affected models are: 2000, 2100, 2106, 2112, 2125, 2500, 2504, and 4100.
    Affected if The device model matches one of the listed Cisco WLC models.
  2. Check if TELNET is enabled
    Run 'show telnet' on the WLC CLI to display the current TELNET server status and configuration.
    Affected if TELNET is enabled for management access (output shows TELNET server is enabled).
  3. Verify current TELNET session state
    Run 'show telnet session' or 'show session' to display active and recent TELNET connections, including session count and status.
    Affected if There are numerous incomplete or zombie TELNET sessions indicating resource exhaustion.
  4. Check system resource usage
    Run 'show system resources' or 'show memory' to display CPU and memory utilization on the WLC.
    Affected if System resources are abnormally high or depleted, which could indicate the resource exhaustion condition.
  5. Test TELNET service availability
    Attempt a TELNET connection to the WLC management IP on port 23. Observe whether the connection succeeds, fails, or times out.
    Affected if TELNET connections fail to establish or the service is unresponsive, indicating potential outage from the vulnerability.

The environment is affected if the device is a Cisco WLC model listed in the affected products and TELNET management access is currently enabled, with observed service issues or abnormal session states.

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

Disable TELNET access on the WLC and enforce SSH for management access. If TELNET is required, restrict it to specific management networks and implement connection rate limiting.

Fix this in 2000 Wireless Lan Controller Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2013-1235 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2013-1235 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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