CVE-2017-3820 Cisco CVE debrief

Who should care

Network and security teams responsible for Cisco ASR 1000 Series routers, especially environments exposing SNMP management access on the affected IOS XE releases, should treat this as a service-availability risk.

Technical summary

The CVE description and NVD record identify a flaw in SNMP functions on Cisco ASR 1000 Series routers. NVD marks Cisco IOS XE 3.13.6s, 3.16.2s, and 3.17.1s as vulnerable CPEs, and the record also lists known affected releases 15.5(3)S2.1 and 15.6(1)S1.1. An authenticated remote attacker can induce high CPU usage on the affected device, causing a denial-of-service condition. NVD assigns CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H and CWE-665.

Defensive priority

Medium. This is an availability-focused network device issue that can disrupt router management or forwarding stability, but it requires authenticated access and is not marked as known exploited in the supplied data.

Recommended defensive actions

• Upgrade affected Cisco IOS XE releases to a fixed version listed in the CVE record: 15.4(3)S6.1, 15.4(3)S6.2, 15.5(3)S2.2, 15.5(3)S3, 15.6(0.22)S0.23, 15.6(1)S2, 16.2(0.295), 16.3(0.94), or 15.5.3S3.
• Inventory Cisco ASR 1000 Series routers and confirm whether any are running the affected IOS XE versions cited in the record.
• Review SNMP-enabled management paths on these routers and prioritize remediation for devices that are reachable by authenticated remote administrators or management systems.
• Use the Cisco vendor advisory referenced by NVD to validate the correct fixed release for each affected platform and software train.

Evidence notes

Based on the CVE record and NVD metadata supplied in the source corpus. Evidence includes the published CVE description, NVD CVSS vector, CWE-665 classification, vulnerable CPE criteria, and the Cisco vendor-advisory reference listed in NVD references. No exploit details or unsupported mitigation claims were used.

Official resources