What is CVE-2017-3849?

CVE-2017-3849 is a high-severity vulnerability in Cisco iOS, classified under Improper Input Validation. CVSS score: 7.4/10. Published 2017-03-21.

How severe is CVE-2017-3849?

High severity. CVSS v3 base score is 7.4 out of 10.

Improper input validation in Cisco iOS

CVE-2017-3849

A vulnerability in the Autonomic Networking Infrastructure (ANI) registrar feature of Cisco IOS Software (possibly 15.2 through 15.6) and Cisco IOS XE Software (possibly 3.7 through 3.18, and 16) could allow an unauthenticated, adjacent 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 autonomic network channel discovery packet to a device that has all the following characteristics: (1) running a Cisco IOS Software or Cisco IOS XE Software release that supports the ANI feature; (2) configured as an autonomic registrar; (3) has a whitelist configured. An exploit could allow the attacker to cause the affected device to reload. Note: Autonomic networking should be configured with a whitelist. Do not remove the whitelist as a workaround. Cisco Bug IDs: CSCvc42717.

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

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

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.008 (53.8th percentile), scored 2026-10-07.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 53.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · 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… (Vendor Advisory)
www.securityfocus.com/bid/96972 (VDB Entry, Third Party Advisory, vdb-entry)
www.securitytracker.com/id/1038064 (vdb-entry)

Frequently asked questions

What is CVE-2017-3849?: CVE-2017-3849 is a high-severity vulnerability in Cisco iOS, classified under Improper Input Validation. CVSS score: 7.4/10. Published 2017-03-21.
How severe is CVE-2017-3849?: High severity. CVSS v3 base score is 7.4 out of 10.