Cisco IOS XE Software Zone Based Firewall DoS (cisco-sa-zbfw-94ckG4G)

High Nessus Plugin ID 141460

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VPR Score: 4.4


The remote device is missing a vendor-supplied security patch.


According to its self-reported version, IOS-XE is affected by multiple denial of service vulnerabilities in the zone-based firewall feature due to incomplete handling of Layer 4 packets through the device. An unauthenticated, remote attacker can exploit these, by sending a certain sequence of traffic patterns through the device, to cause the device to reload or stop forwarding traffic through the firewall, causing a denial of service.


Upgrade to the relevant fixed version referenced in Cisco bug IDs CSCvs71952 and CSCvt52986.

See Also

Plugin Details

Severity: High

ID: 141460

File Name: cisco-sa-zbfw-94ckG4G-iosxe.nasl

Version: 1.7

Type: local

Family: CISCO

Published: 2020/10/15

Updated: 2021/01/08

Dependencies: 67217

Risk Information

Risk Factor: High

VPR Score: 4.4

CVSS Score Source: CVE-2020-3480

CVSS v2.0

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Temporal Vector: CVSS2#E:U/RL:OF/RC:C

CVSS v3.0

Base Score: 8.6

Temporal Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:cisco:ios_xe

Required KB Items: Host/Cisco/IOS-XE/Version

Exploit Ease: No known exploits are available

Patch Publication Date: 2020/09/24

Vulnerability Publication Date: 2020/09/24

Reference Information

CVE: CVE-2020-3421, CVE-2020-3480

CISCO-BUG-ID: CSCvs71952, CSCvt52986

CISCO-SA: cisco-sa-zbfw-94ckG4G

IAVA: 2020-A-0439

CWE: 754