Is CVE-2017-3857 being actively exploited?

CVE-2017-3857 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2017-3857?

CVE-2017-3857 has a CVSS 3.1 base score of 7.5 (HIGH).

CVE-2017-3857

HIGH · CVSS 7.5EPSS 2.6%EU EUVD

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.

Key facts

CVSS score: 7.5 (v3.1)
Severity: HIGH
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-399
EPSS score: 2.6% (85th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2017-12974)
Published: March 22, 2017
NVD last modified: June 17, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2017-12974 in the EU Vulnerability Database. Last updated in EUVD on August 5, 2024.

View on the EU Vulnerability Database

Affected products

cisco / ios
cisco / ios xe

Certified products that may be affected

8 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Cisco Catalyst 4500 Series Wired Access Switches running IOS-XE 3.10 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-10906-2018 - archived
Cisco Catalyst 3K/4K Wired Access Switches running IOS-XE 3.8.0E - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10688-2016 - archived
Cisco Aggregation Services Router (ASR) 1000 Series, IOS XE 3.13 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10609-2015 - archived
Cisco Integrated Services Router 4400 Series (ISR-4400), IOS XE 3.13.0 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10600-2015 - archived
Cisco Catalyst 3650, 3850, 4500E (Sup7E, Sup7LE, Sup8E), 4500X, 4500XF running IOS-XE 3.6.1S - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10607-2014 - archived

See all 8 in the Security Certifications Explorer.

References

http://www.securityfocus.com/bid/97010(Third Party Advisory, VDB Entry)
http://www.securitytracker.com/id/1038100(Third Party Advisory, VDB Entry)
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170322-l2tp(VDB Entry)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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