dbcve.org
iOSOperating system · Cisco

CVE-2014-7997

MEDIUM · 6.1 CVSS v2.0 Published 2014-11-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
66/100
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
The DHCP implementation in Cisco IOS on Aironet access points does not properly handle error conditions with short leases and unsuccessful lease-renewal attempts, which allows remote attackers to cause a denial of service (device restart) by triggering a transition into a recovery state that was intended to involve a network-interface restart but actually involves a full device restart, aka Bug ID CSCtn16281.

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

The DHCP implementation in Cisco IOS on Aironet access points has a logic error in error handling for short leases and failed renewal attempts. When these conditions occur, the device enters a recovery state that should trigger only a network-interface restart but instead causes a full device restart, resulting in denial of service.

MitigationApply the relevant Cisco IOS software update for Aironet access points once available from Cisco. Until then, monitor for unexpected device restarts and consider network segmentation to limit exposure to remote attackers triggering the vulnerable code path.

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
iOSOperating 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
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete

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

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 is a Cisco Aironet access point running IOS
    Identify the device model using 'show version' or 'show hardware' commands. Look for 'Aironet' in the product description and verify IOS is the operating system.
    Affected if Device is a Cisco Aironet access point running Cisco IOS
  2. Verify DHCP client is enabled on the device
    Use 'show ip interface brief' or 'show running-config | include dhcp' to check if DHCP client is configured on any interface.
    Affected if DHCP client is enabled and configured on the access point
  3. Check DHCP lease configuration for short lease times
    Use 'show ip dhcp pool' or 'show dhcp lease' to examine configured lease durations.
    Affected if DHCP lease time is configured as a short duration (minutes rather than hours or days)
  4. Monitor for unexpected full device restarts
    Use 'show reload' to check for scheduled reloads, and 'show logging' or 'show tech-support' to look for crashinfo or unexpected reload reasons. Compare against expected interface-level restarts.
    Affected if Device is experiencing unexpected full system restarts (complete reload) rather than isolated interface restarts
  5. Check for DHCP renewal failure messages in logs
    Use 'show logging' or examine syslog records for DHCP-related error messages, failed renewal attempts, or recovery state entries.
    Affected if DHCP renewal failures or recovery state messages are logged in conjunction with device restarts

If the device is a Cisco Aironet access point running IOS with DHCP enabled and experiencing unexpected full system restarts instead of network-interface-only restarts, the environment is affected by this vulnerability.

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 relevant Cisco IOS software update for Aironet access points once available from Cisco. Until then, monitor for unexpected device restarts and consider network segmentation to limit exposure to remote attackers triggering the vulnerable code path.

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2014-7997 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