What is CVE-2017-3856?

CVE-2017-3856 is a high-severity vulnerability in Cisco iOS Xe, classified under CWE-399. CVSS score: 7.5/10. Published 2017-03-22.

How severe is CVE-2017-3856?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Cisco iOS Xe

CVE-2017-3856

A vulnerability in the web user interface of Cisco IOS XE 3.1 through 3.17 could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to insufficient resource handling by the affected software when the web user interface is under a high load. An attacker could exploit this vulnerability by sending a high number of requests to the web user interface of the affected software. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. To exploit this vulnerability, the attacker must have access to the management interface of the affected software, which is typically connected to a restricted management network. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS XE Software, if the web user interface of the software is enabled. By default, the web user interface is not enabled. Cisco Bug IDs: CSCup70353.

Published 2017-03-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.025 (83.9th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 84th percentile — 83.9% 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 Xe — versions 3.1.0s, 3.1.0sg, 3.1.1s
Cisco iOS Xe — versions Cisco IOS XE

Weakness classification (CWE)

References

www.securitytracker.com/id/1038101 (vdb-entry)
tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170322… (Vendor Advisory)
www.securityfocus.com/bid/97007 (VDB Entry, Third Party Advisory, vdb-entry)

Frequently asked questions

What is CVE-2017-3856?: CVE-2017-3856 is a high-severity vulnerability in Cisco iOS Xe, classified under CWE-399. CVSS score: 7.5/10. Published 2017-03-22.
How severe is CVE-2017-3856?: High severity. CVSS v3 base score is 7.5 out of 10.