CVE-2020-3480

Cisco IOS XE Software Zone-Based Firewall Denial of Service Vulnerabilities

HIGH
8.6
CVSS Score
Published: September 24, 2020 at 05:52 PM UTC
Updated: June 17, 2026 at 03:18 AM UTC
26 products affected across 1 vendorIOS XeAsr 1002-xAsr 1006

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Severity
HIGH8.6
Exploit prediction
EPSS 1%
SSVC
No known exploit

Description

Multiple vulnerabilities in the Zone-Based Firewall feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload or stop forwarding traffic through the firewall. The vulnerabilities are due to incomplete handling of Layer 4 packets through the device. An attacker could exploit these vulnerabilities by sending a certain sequence of traffic patterns through the device. A successful exploit could allow the attacker to cause the device to reload or stop forwarding traffic through the firewall, resulting in a denial of service. For more information about these vulnerabilities, see the Details section of this advisory.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

All versions
cisco-1100-integrated-services-router (environment) · cisco-1101-integrated-services-router (environment) · cisco-1109-integrated-services-router (environment) · cisco-1111x-integrated-services-router (environment) · cisco-111x-integrated-services-router (environment) · cisco-1120-integrated-services-router (environment) · cisco-1160-integrated-services-router (environment) · cisco-4221-integrated-services-router (environment) · cisco-4321-integrated-services-router (environment) · cisco-4331-integrated-services-router (environment) · cisco-4351-integrated-services-router (environment) · cisco-4431-integrated-services-router (environment) · cisco-4451-x-integrated-services-router (environment) · cisco-4461-integrated-services-router (environment) · cisco-asr-1001-hx (environment) · cisco-asr-1001-x (environment) · cisco-asr-1002-hx (environment) · cisco-asr-1002-x (environment) · cisco-asr-1004 (environment) · cisco-asr-1006 (environment) · cisco-asr-1006-x (environment) · cisco-asr-1009-x (environment) · cisco-asr-1013 (environment) · cisco-cloud-services-router-1000v (environment) · cisco-integrated-services-virtual-router (environment)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.6HIGHcisco
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-754

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