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CVE-2021-1394 Details

Description

A vulnerability in the ingress traffic manager of Cisco IOS XE Software for Cisco Network Convergence System (NCS) 520 Routers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition in the web management interface of an affected device. This vulnerability is due to incorrect processing of certain IPv4 TCP traffic that is destined to an affected device. An attacker could exploit this vulnerability by sending a large number of crafted TCP packets to the affected device. A successful exploit could allow the attacker to cause the web management interface to become unavailable, resulting in a DoS condition. Note: This vulnerability does not impact traffic that is going through the device or going to the Management Ethernet interface of the device.

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:5.3 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CNA: [email protected]CVSS-B:5.3 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ncs520-tcp-ZpzzOxB	CVE	Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ncs520-tcp-ZpzzOxB	[email protected]	Vendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
NVD-CWE-noinfo	Insufficient Information to Classify Weakness	[email protected]
CWE-399	Resource Management Errors	[email protected]

Affected Products

Product	Versions
cisco ios xe	16.10.1 16.10.1a 16.10.1b 16.10.1c 16.10.1d
CPE cpe:2.3:o:cisco:ios_xe:16.10.1:::::::* cpe:2.3:o:cisco:ios_xe:16.10.1a:::::::* cpe:2.3:o:cisco:ios_xe:16.10.1b:::::::* cpe:2.3:o:cisco:ios_xe:16.10.1c:::::::* cpe:2.3:o:cisco:ios_xe:16.10.1d:::::::* cpe:2.3:o:cisco:ios_xe:16.10.1e:::::::* cpe:2.3:o:cisco:ios_xe:16.10.1f:::::::* cpe:2.3:o:cisco:ios_xe:16.10.1g:::::::* cpe:2.3:o:cisco:ios_xe:16.10.1s:::::::* cpe:2.3:o:cisco:ios_xe:17.2.1v:::::::* Remediation No remediation found in references.

Product

Versions

cisco ios xe

16.10.1

16.10.1a

16.10.1b

16.10.1c

16.10.1d

CPE

cpe:2.3:o:cisco:ios_xe:16.10.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:16.10.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:16.10.1b:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:16.10.1c:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:16.10.1d:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:16.10.1e:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:16.10.1f:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:16.10.1g:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:16.10.1s:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.2.1v:*:*:*:*:*:*:*

Remediation

No remediation found in references.

Change History

8 change records found show changes

Date	Action	Recorded By
Jun 17, 2026	CVE Modified	CISA-ADP
Jun 17, 2026	CVE Modified	[email protected]
Nov 21, 2024	CVE Modified	CVE
May 14, 2024	CVE Modified	[email protected]
Nov 7, 2023	CVE Modified	[email protected]
Apr 25, 2022	Reanalysis	[email protected]
Mar 29, 2021	Initial Analysis	[email protected]
Mar 24, 2021	CVE Modified	[email protected]