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CVE Record

CVE-2017-6740: The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple...

The 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.

HighCVSS 8.8Known exploitedUpdated
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This flaw affects Cisco IOS and IOS XE devices with SNMP enabled. An attacker who has the required SNMP community string or SNMPv3 credentials could crash the device or take full control. Because CISA lists this CVE in KEV, treat exposed network infrastructure as urgent to verify and remediate.

Executive priority

Prioritize remediation for internet-facing or broadly reachable network devices first. This is not a routine endpoint bug; successful exploitation can disrupt routing and switching or give an attacker control of infrastructure.

Technical view

CVE-2017-6740 is a buffer overflow in the SNMP subsystem of Cisco IOS and IOS XE. Crafted SNMP packets over IPv4 or IPv6 can trigger code execution or reload when directed at an affected device. SNMP v1, v2c, and v3 are affected; exploitation requires the relevant community string or SNMPv3 credentials.

Likely exposure

Exposure is likely on Cisco IOS or IOS XE devices with SNMP enabled that have not excluded the affected MIBs or OIDs. Devices reachable by untrusted networks or using widely known SNMP credentials carry higher operational risk.

Exploitation context

CISA KEV status supports known exploitation. The provided sources do not include exploit details, campaign attribution, or current exploitation volume. The vulnerability is still important because successful exploitation can affect routers, switches, and other network infrastructure directly.

Researcher notes

The evidence supports Cisco IOS and IOS XE SNMP buffer overflow exposure, authenticated network attack requirements, and KEV status. The source bundle does not provide proof-of-concept details, specific exploited versions beyond the affected list, or telemetry on exploitation prevalence.

Mitigation direction

  • Inventory Cisco IOS and IOS XE devices with SNMP enabled.
  • Apply Cisco's documented workaround for affected MIBs or OIDs.
  • Use Cisco IOS Software Checker to identify fixed software.
  • Upgrade affected devices to Cisco-recommended fixed releases.
  • Review SNMP community strings and SNMPv3 credentials for exposure.

Validation and detection

  • Confirm whether SNMP is enabled on each Cisco IOS or IOS XE device.
  • Verify device software versions against Cisco advisory guidance.
  • Check whether affected MIBs or OIDs are explicitly excluded.
  • Confirm SNMP management access is limited to expected sources.
  • Review logs for unexpected SNMP activity targeting infrastructure devices.
Prepared
Confidence
high
Sources
4

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-119: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2017-6740 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.8 (3.0)
Known Exploited
Yes
Published

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
4Source links

CISA KEV status

Status
Known exploited
Source
CISA / ADP
Date added
Not provided

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.8CVSS 3.0HighCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

8.8High
CVSS 3.0 vector shape for CVE-2017-6740Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoIOS12.2(14)ZA, 12.2(14)ZA3, 12.2(14)ZA2, 12.2(14)ZA5, 12.2(14)ZA4, 12.2(14)ZA6, 12.2(14)ZA7, 12.2(25)SE2, 12.2(29)SV2, 12.2(17d)SXB6, 12.2(17d)SXB11, 12.2(17d)SXB7, 12.2(17d)SXB4, 12.2(17d)SXB2, 12.2(17d)SXB3, 12.2(17d)SXB5, 12.2(17d)SXB10, 12.2(17d)SXB8, 12.2(17d)SXB11a, 12.2(17d)SXB1, 12.2(17d)SXB9, 12.2(18)SO1, 12.2(18)SO3, 12.2(18)SO2, 12.2(18)SXF, 12.2(18)SXF5, 12.2(18)SXF6, 12.2(18)SXF15, 12.2(18)SXF10, 12.2(18)SXF17b, 12.2(18)SXF4, 12.2(18)SXF15a, 12.2(18)SXF3, 12.2(18)SXF17, 12.2(18)SXF12, 12.2(18)SXF8, 12.2(18)SXF10a, 12.2(18)SXF16, 12.2(18)SXF7, 12.2(18)SXF17a, 12.2(18)SXF14, 12.2(18)SXF12a, 12.2(18)SXF9, 12.2(18)SXF13, 12.2(18)SXF2, 12.2(18)SXF11, 12.2(28)ZX, 12.2(33)STE0, 15.0(1)XO1, 15.0(1)XO, 15.0(2)XO, 15.0(2)SG11a, 15.0(1)EX, 15.0(2)EX2, 15.0(2)EX8, 15.0(2)EX10, 15.0(2)EX11, 15.0(2)EX13, 15.0(2)EX12, 15.1(2)SY9, 15.1(3)MRA3, 15.1(3)MRA4, 15.1(3)SVB1, 15.1(3)SVB2, 15.1(3)SVD, 15.1(3)SVD1, 15.1(3)SVD2, 15.1(3)SVF, 15.1(3)SVF1, 15.1(3)SVE, 15.1(3)SVG, 15.1(3)SVJ2Listed
IntelliShieldUniversal ProductN/AListed
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-119 · source CWE mapping

Improper Restriction of Operations within the Bounds of a Memory Buffer

Improper Restriction of Operations within the Bounds of a Memory Buffer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.