iOSOperating system · Cisco
CVE-2017-6736
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 · uneditedThe Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple vulnerabilities that could allow an authenticated, remote attacker to remotely execute code on an affected system or cause an affected system to reload. An attacker could exploit these vulnerabilities by sending a crafted SNMP packet to an affected system via IPv4 or IPv6. Only traffic directed to an affected system can be used to exploit these vulnerabilities. The vulnerabilities are due to a buffer overflow condition in the SNMP subsystem of the affected software. The vulnerabilities affect all versions of SNMP - Versions 1, 2c, and 3. To exploit these vulnerabilities via SNMP Version 2c or earlier, the attacker must know the SNMP read-only community string for the affected system. To exploit these vulnerabilities via SNMP Version 3, the attacker must have user credentials for the affected system. A successful exploit could allow the attacker to execute arbitrary code and obtain full control of the affected system or cause the affected system to reload. Customers are advised to apply the workaround as contained in the Workarounds section below. Fixed software information is available via the Cisco IOS Software Checker. All devices that have enabled SNMP and have not explicitly excluded the affected MIBs or OIDs should be considered vulnerable. There are workarounds that address these vulnerabilities.
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 confidenceCVE-2017-6736 is a buffer overflow vulnerability in the SNMP subsystem of Cisco IOS and IOS XE Software. An authenticated remote attacker can send crafted SNMP packets (via IPv4 or IPv6) to execute arbitrary code or cause system reload. Exploitation requires knowledge of SNMP community strings (v1/v2c) or valid SNMPv3 user credentials.
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
>= 12.0, <= 12.4>= 15.0, <= 15.6
Ios XeOperating system
>= 2.2.0, <= 3.17CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 Cisco IOS or IOS XE versionRun 'show version' to display the running software versionAffected if The version falls within 12.0-12.4 or 15.0-15.6 for Cisco iOS, or 2.2.0-3.17 for Cisco IOS XE
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Verify SNMP is enabledRun 'show snmp' to check if SNMP is running and configuredAffected if SNMP is enabled (the vulnerability only exists when the SNMP subsystem is active)
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Check SNMP v2c community stringsRun 'show snmp community' to list configured community stringsAffected if Read-write or read-only community strings are configured (exploitation requires SNMP v2c credentials)
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Check SNMP v3 usersRun 'show snmp user' to list SNMPv3 usersAffected if SNMPv3 users are configured (exploitation requires SNMP v3 credentials)
You are affected if your device runs Cisco iOS 12.0-12.4, 15.0-15.6, or Cisco IOS XE 2.2.0-3.17 AND has SNMP enabled with v2c community strings or v3 user credentials configured.
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.
dbcve · scopedApply Cisco patches via the IOS Software Checker, or implement workarounds such as disabling SNMP, restricting SNMP access via ACLs, or changing SNMP community strings to limit exposure.
Fixed releases vary by iOS/IOS XE train; use Cisco IOS Software Checker at tools.cisco.com to identify the specific fixed release for your device
- 1. Identify the exact Cisco IOS or IOS XE version currently running on the device using 'show version' command
- 2. Use the Cisco IOS Software Checker (tools.cisco.com) to check for security advisories and available fixed releases for this specific device
- 3. If upgrading to a fixed release is not immediately possible, implement the available workarounds: disable SNMP if not required, or restrict SNMP access to trusted management stations using ACLs
- 4. If SNMP is required, consider using SNMPv3 with authentication and encryption instead of SNMPv1/v2c, and ensure strong community strings if SNMPv2c must be used
- 5. Apply the fixed software release following standard Cisco upgrade procedures
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in iOS
Exploited in the wild — priority engagement
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 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 $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-6736 — 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-2017-6736 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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- Version or environment caveats, and links to real fixes
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