CVEs / CVE-2017-6740

CVE-2017-6740: Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability

• Known exploited in the CISA KEV catalog since 3 Mar 2022
• high 8.8 CVSS 3.1 (NVD)
• EPSS 11.1% chance of exploitation in the next 30 days, higher than 95% of CVEs (30 Oct 2026)
• Last changed at its sources 17 Jun 2026

Summary

The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE contains a vulnerability that could allow an authenticated, remote attacker to remotely execute code on an affected system or cause an affected system to reload.

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.

Affected and fixed versions

Exploitation

Severity

References

• CVE-2017-6740 on NVD
• CVE-2017-6740 in the CISA KEV catalog
• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp US Government Resource
• http://www.securityfocus.com/bid/99345 Broken Link, Third Party Advisory, VDB Entry
• http://www.securitytracker.com/id/1038808 Broken Link, Third Party Advisory, VDB Entry
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp Vendor Advisory
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-6740 US Government Resource