CVE-2017-6736: Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability

Vulnerability summary

CVE-2017-6736 is a high (CVSS 9.0) vulnerability in Cisco IOS and IOS XE Software. It is known to be exploited: CISA lists it, first on 03-03-2022. EPSS estimates a 70.35% chance of exploitation in the next 30 days, higher than 99.3% of scored vulnerabilities. 2 public exploits are recorded.

Timeline

1. 17-07-2017
   PublishedVulnerability first disclosed.
2. 03-03-2022
   Added to CISA KEVCisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability
3. 24-03-2022
   CISA remediation dueApply updates per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

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.

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferThe product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.