What is CVE-2017-3850?

CVE-2017-3850 is a medium-severity vulnerability in Cisco iOS, classified under Improper Input Validation. CVSS score: 5.9/10. Published 2017-03-21.

How severe is CVE-2017-3850?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Improper input validation in Cisco iOS

CVE-2017-3850

A vulnerability in the Autonomic Networking Infrastructure (ANI) feature of Cisco IOS Software (15.4 through 15.6) and Cisco IOS XE Software (3.7 through 3.18, and 16) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to incomplete input validation on certain crafted packets. An attacker could exploit this vulnerability by sending a crafted IPv6 packet to a device that is running a Cisco IOS Software or Cisco IOS XE Software release that supports the ANI feature. A device must meet two conditions to be affected by this vulnerability: (1) the device must be running a version of Cisco IOS Software or Cisco IOS XE Software that supports ANI (regardless of whether ANI is configured); and (2) the device must have a reachable IPv6 interface. An exploit could allow the attacker to cause the affected device to reload. Cisco Bug IDs: CSCvc42729.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2017-03-21 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.025 (84.2th percentile), scored 2026-10-07.

Low probability of exploitation in the next 30 days, but still tracked. 84th percentile — 84.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.025 · newest: 0.025 · change: 0.000

Affected products

Cisco iOS — versions 15.6(1)t, 15.3(3)s2, 15.5\(1\)s3
Cisco iOS Xe — versions 3.7.0e, 3.7.1e, 3.7.2e
Cisco iOS And Xe — versions Cisco IOS and IOS XE

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170320… (Mitigation, Vendor Advisory)
www.securitytracker.com/id/1038065 (VDB Entry, Third Party Advisory, vdb-entry)
www.securityfocus.com/bid/96971 (VDB Entry, Third Party Advisory, vdb-entry)

Frequently asked questions

What is CVE-2017-3850?: CVE-2017-3850 is a medium-severity vulnerability in Cisco iOS, classified under Improper Input Validation. CVSS score: 5.9/10. Published 2017-03-21.
How severe is CVE-2017-3850?: Medium severity. CVSS v3 base score is 5.9 out of 10.