What Is Cisco IOS SNMP?
CVE-2017-6742 is one of multiple distinct buffer overflow vulnerabilities in the Cisco IOS and IOS XE SNMP subsystem disclosed in June 2017 advisory cisco-sa-20170629-snmp. Unlike most of the other CVEs from this advisory (which were added to KEV in March 2022), CVE-2017-6742 was added separately to the KEV catalog in April 2023 — reflecting continued confirmed exploitation of this specific SNMP OID vulnerability more than a year after the other advisory CVEs were catalogued.
Overview
CVE-2017-6742 is a buffer overflow in a specific SNMP OID handler in Cisco IOS and IOS XE that can allow code execution or device reload. An attacker with valid SNMP credentials sends a crafted SNMP packet referencing the vulnerable OID. Its separate April 2023 KEV addition (deadline May 10, 2023) — one year after the other advisory CVEs — indicates this specific OID was actively targeted in 2023 exploitation campaigns. See CVE-2017-6736 for full context on this advisory.
Affected Versions
Cisco IOS and IOS XE with SNMP enabled. Use cisco-sa-20170629-snmp and the Cisco IOS Software Checker for specific version identification.
Technical Details
CVE-2017-6742 is a buffer overflow (CWE-119) in a specific SNMP OID handler. A crafted SNMP packet from an authenticated attacker enables code execution or device reload. Its 2023 KEV addition (vs March 2022 for other advisory CVEs) indicates this specific OID remained in active attacker use.
| Attribute | Detail |
|---|---|
| Attack Vector | Network — SNMP (UDP port 161) |
| Authentication | SNMP credentials required (PR:L) |
| KEV Addition | April 19, 2023 (separate from other advisory CVEs added March 2022) |
| Advisory | cisco-sa-20170629-snmp |
Remediation
Apply Cisco IOS security update per cisco-sa-20170629-snmp. Additionally: disable SNMP if not required, use SNMPv3 with authpriv, apply SNMP ACLs, and change default community strings. See CVE-2017-6736 for detailed remediation steps.
Key Details
| Property | Value |
|---|---|
| CVE ID | CVE-2017-6742 |
| Vendor / Product | Cisco — IOS and IOS XE Software |
| NVD Published | 2017-07-17 |
| NVD Last Modified | 2026-01-12 |
| CVSS 3.1 Score | 8.8 |
| CVSS 3.1 Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Severity | HIGH |
| CWE | CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer find similar ↗ |
| CISA KEV Added | 2023-04-19 |
| CISA KEV Deadline | 2023-05-10 |
| Known Ransomware Use | No |
CVSS 3.1 Breakdown
Required Action
Timeline
| Date | Event |
|---|---|
| 2017-06-29 | Cisco releases advisory cisco-sa-20170629-snmp covering multiple SNMP RCE vulnerabilities including CVE-2017-6742 |
| 2017-07-17 | CVE-2017-6742 published by NVD |
| 2023-04-19 | Added to CISA Known Exploited Vulnerabilities catalog (separate KEV addition from others in this advisory) |
| 2023-05-10 | CISA BOD 22-01 remediation deadline |
References
| Resource | Type |
|---|---|
| NVD — CVE-2017-6742 | Vulnerability Database |
| CISA KEV Catalog Entry | US Government |
| Cisco Security Advisory cisco-sa-20170629-snmp | Vendor Advisory |