Small Business Ip Phone FirmwareOperating system · Cisco
CVE-2017-12259
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 implementation of Session Initiation Protocol (SIP) functionality in Cisco Small Business SPA51x Series IP Phones could allow an unauthenticated, remote attacker to cause an affected device to become unresponsive, resulting in a denial of service (DoS) condition. The vulnerability is due to the improper handling of SIP request messages by an affected device. An attacker could exploit this vulnerability by sending malformed SIP messages to an affected device. A successful exploit could allow the attacker to cause the affected device to become unresponsive, resulting in a DoS condition that persists until the device is restarted manually. This vulnerability affects Cisco Small Business SPA51x Series IP Phones that are running Cisco SPA51x Firmware Release 7.6.2SR1 or earlier. Cisco Bug IDs: CSCvc63982.
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 the SIP implementation of Cisco Small Business SPA51x Series IP Phones allows an unauthenticated remote attacker to send malformed SIP request messages that cause the device to become completely unresponsive, requiring manual restart to recover.
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
Small Business Ip Phone FirmwareOperating system
<= 7.6.2CVSS 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:3.0/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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Confirm device model is Cisco SPA51x SeriesAccess the phone's web interface or check the device label/menu to verify the exact model number (SPA511G, SPA512G, SPA514G, etc.) matches the SPA51x series.Affected if The device is not a Cisco Small Business SPA51x series phone.
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Check installed firmware versionLog into the phone's web admin interface and navigate to the System or Administration page to view the current firmware version, or use the phone's menu to access the device information screen.Affected if The firmware version is 7.6.2 or lower.
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Verify SIP protocol is enabledCheck the phone's configuration through the web interface under SIP settings or Phone lines configuration to determine if SIP (Session Initiation Protocol) is actively enabled for making calls.Affected if SIP is enabled and the firmware version is <= 7.6.2.
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Check device network accessibilityAttempt to ping the phone's IP address or access its web interface to confirm the device is currently powered on and reachable on the network.Affected if The device is reachable on the network with SIP enabled and vulnerable firmware.
A user is affected if they own a Cisco Small Business SPA51x Series IP Phone running firmware version 7.6.2 or earlier with SIP protocol enabled and the device is accessible on the network.
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 dataUpdate Cisco SPA51x firmware beyond Release 7.6.2SR1 to patch the vulnerability. If no updated firmware is available, isolate affected devices on a restricted network segment and implement SIP traffic filtering at the network edge to block malformed SIP messages.
Fix this in Small Business Ip Phone Firmware
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-12259 — 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-2017-12259 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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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.
- 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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