Cisco IOS and IOS XE SNMP Remote Code Execution Vulnerability

Historical catalog analysis: CISA added this entry on April 19, 2023. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.

What the vulnerability is

Retrospective reports indicate a vulnerability (CVE-2017-6742) within the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE software. This flaw, categorized as CWE-119, could allow an authenticated remote attacker to execute arbitrary code on the affected system or trigger a system reload.

Exposure and applicability

This vulnerability applies to devices running affected versions of Cisco IOS and IOS XE. In industrial environments, these operating systems frequently power the routers and switches that form the backbone of SCADA and OT networks. Because the attack vector requires authentication, exposure is highest in environments where SNMP community strings or credentials are weak, shared across multiple sites, or managed via insecure protocols.

Remediation priorities

Based on the inclusion of this vulnerability in CISA’s Known Exploited Vulnerabilities catalog as of April 19, 2023, we analyze the following priorities for OT asset owners:

• Inventory and Version Audit: Identify all Cisco networking hardware within the industrial control system (ICS) perimeter and verify if they are running affected versions of IOS or IOS XE.
• Update Application: Apply software updates according to vendor instructions. Given the potential for system reloads, these updates should be scheduled during planned maintenance windows to avoid unplanned process downtime.
• SNMP Hardening: As a complementary measure to patching, review SNMP configurations. This includes disabling SNMP where it is not required for operations and ensuring that authentication credentials are not using default settings.

How to validate remediation

To verify that the risk has been reduced, operators should perform the following:

1. Version Verification: Confirm through a configuration audit or command-line check that the running software version matches the patched release specified by the vendor.
2. Configuration Review: Validate that SNMP access is restricted to authorized management workstations via Access Control Lists (ACLs), reducing the potential for an authenticated attacker to reach the subsystem from unauthorized network segments.

Limits and open questions

Updating the software does not inherently secure the rest of the network; it specifically addresses the flaw in the SNMP subsystem. It remains unknown whether this vulnerability has been utilized in specific ransomware campaigns. Additionally, while CISA established a May 10, 2023, deadline for federal agencies, private sector asset owners must determine their own remediation timelines based on their specific operational risk profiles and maintenance schedules.

Source and editorial note

CVE-2017-6742: Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability · Source date: April 19, 2023 · Retrieved August 31, 2026.

Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.

Archive date: April 22, 2023. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: October 09, 2026 at 01:24 UTC.

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