What Is Cisco IOS SNMP?
CVE-2017-6738 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. Each CVE in this advisory (6736–6744) represents a separate OID-specific buffer overflow. All require SNMP authentication and are addressed by the same IOS software update.
Overview
CVE-2017-6738 is a buffer overflow in a specific SNMP OID handler in Cisco IOS and IOS XE. An attacker with valid SNMP credentials can send a crafted SNMP packet to execute code on the device or cause it to reload. All CVEs in advisory cisco-sa-20170629-snmp (6736–6744) are addressed by the same IOS software update. 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-2017-6738 is a buffer overflow (CWE-119) in the handler for a specific SNMP OID. Exploitation requires valid SNMP credentials. A crafted SNMP packet triggers the overflow enabling code execution or reload.
| Attribute | Detail |
|---|---|
| Attack Vector | Network — SNMP (UDP port 161) |
| Authentication | SNMP credentials required (PR:L) |
| Advisory | cisco-sa-20170629-snmp (shared with CVE-2017-6736, 6737, 6739–6744) |
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-2017-6738 |
| Vendor / Product | Cisco — IOS and IOS XE Software |
| NVD Published | 2017-07-17 |
| NVD Last Modified | 2025-10-22 |
| 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 | 2022-03-03 |
| CISA KEV Deadline | 2022-03-24 |
| 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-2017-6738 |
| 2017-07-17 | CVE-2017-6738 published by NVD |
| 2022-03-03 | Added to CISA Known Exploited Vulnerabilities catalog |
| 2022-03-24 | CISA BOD 22-01 remediation deadline |
References
| Resource | Type |
|---|---|
| NVD — CVE-2017-6738 | Vulnerability Database |
| CISA KEV Catalog Entry | US Government |
| Cisco Security Advisory cisco-sa-20170629-snmp | Vendor Advisory |