CVE-2017-3857

Name: CVE-2017-3857
Creator: NVD / NIST
Published: 2017-03-22T19:59:00.307+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.59%

Last modified Jun 17, 2026

CVE-2017-3857 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. A vulnerability in the Layer 2 Tunneling Protocol (L2TP) parsing function of Cisco IOS (12.0 through 12.4 and 15.0 through 15.6) and Cisco IOS XE (3.1 through 3.18) could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to insufficient validation of L2TP packets. EPSS estimates a 2.59% chance of exploitation in the next 30 days.

Description

A vulnerability in the Layer 2 Tunneling Protocol (L2TP) parsing function of Cisco IOS (12.0 through 12.4 and 15.0 through 15.6) and Cisco IOS XE (3.1 through 3.18) could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to insufficient validation of L2TP packets. An attacker could exploit this vulnerability by sending a crafted L2TP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS or Cisco IOS XE Software if the L2TP feature is enabled for the device and the device is configured as an L2TP Version 2 (L2TPv2) or L2TP Version 3 (L2TPv3) endpoint. By default, the L2TP feature is not enabled. Cisco Bug IDs: CSCuy82078.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

2.59%

83.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Cisco	Ios	>= 12.0, <= 12.4
Cisco	Ios	>= 15.0, <= 15.6
Cisco	Ios Xe	>= 3.1.0, <= 3.18.0

References

http://www.securityfocus.com/bid/97010Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1038100Third Party Advisory, VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170322-l2tpVDB Entry
http://www.securityfocus.com/bid/97010Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1038100Third Party Advisory, VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170322-l2tpVDB Entry

Timeline

Published: Mar 22, 2017
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2017-3857?

How severe is CVE-2017-3857?

CVE-2017-3857 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.59% probability of exploitation in the next 30 days.

How do I fix CVE-2017-3857?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2017-3857?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST