dbcve.org
Spa500 FirmwareOperating system · Cisco

CVE-2015-6403

HIGH · 7.2 CVSS v2.0 Published 2015-12-15
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
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 TFTP implementation on Cisco Small Business SPA30x, SPA50x, SPA51x phones 7.5.7 improperly validates firmware-image file integrity, which allows local users to load a Trojan horse image by leveraging shell access, aka Bug ID CSCut67400.

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 TFTP server on Cisco Small Business SPA30x, SPA50x, and SPA51x phones running firmware 7.5.7 lacks proper firmware-image integrity validation. A local attacker with shell access can load a malicious firmware image (Trojan horse) because the device trusts and executes unvalidated firmware files received via TFTP.

MitigationRestrict physical and administrative access to affected devices and disable TFTP services when not needed. Apply vendor firmware updates when available.

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
Spa500 FirmwareOperating system
Affected:= 7.5.7
Spa300 FirmwareOperating system
Affected:= 7.5.7

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
Local
Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:L/AC:L/Au:N/C:C/I:C/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. Identify the phone model
    Access the device's web administration interface (typically http://[device-ip]/) or physically inspect the device label to determine the exact model number (SPA30x, SPA50x, or SPA51x series)
    Affected if The device is a Cisco SPA30x, SPA50x, or SPA51x phone model
  2. Check the installed firmware version
    In the phone's web interface, navigate to the Admin Login > Device Administration page and locate the firmware version field, or use the phone's status menu to view the current software version
    Affected if The firmware version is exactly 7.5.7
  3. Verify if TFTP server is enabled
    In the phone's web interface, check under Admin Login > System > Configuration > TFTP Server settings, or access the device configuration file to inspect the TFTP Enable parameter
    Affected if TFTP server is enabled and configured on the device

The environment is affected if it contains a Cisco SPA30x, SPA50x, or SPA51x phone running firmware version 7.5.7 with the TFTP server feature enabled.

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

Restrict physical and administrative access to affected devices and disable TFTP services when not needed. Apply vendor firmware updates when available.

Fix this in Spa500 Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA8.0 h
42.0 hours of engineering $7,320
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $11,712.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2015-6403 — 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-2015-6403 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