Vulnerability identifier: #VU20496

Vulnerability risk: Medium

CVSSv3.1: 5.9 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-1977

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco Nexus 9332PQ Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9508 Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9372TX-E Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 93108TC-EX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9504 Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 93120TX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 93108TC-FX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9396TX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9396PX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9516 Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9000 Series Switches in ACI Mode
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9372PX-E Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9348GC-FXP Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 93180YC-EX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 93128TX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 93180YC-FX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9364C Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9372PX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 93180LC-EX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9336PQ ACI Spine Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9372TX Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Nexus 9336C-FX2 Switch
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco NX-OS
Operating systems & Components / Operating system

Vendor: Cisco Systems, Inc

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input due to improper endpoint learning when packets are received on a specific port from outside the ACI fabric and destined to an endpoint located on a border leaf when "Disable Remote Endpoint Learning" has been enabled. A remote attacker can cause a denial of service (DoS) condition on an endpoint device in certain circumstances.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Cisco Nexus 9332PQ Switch: All versions

Cisco Nexus 9508 Switch: All versions

Cisco Nexus 9372TX-E Switch: All versions

Cisco Nexus 93108TC-EX Switch: All versions

Cisco Nexus 9504 Switch: All versions

Cisco Nexus 93120TX Switch: All versions

Cisco Nexus 93108TC-FX Switch: All versions

Cisco Nexus 9396TX Switch: All versions

Cisco Nexus 9396PX Switch: All versions

Cisco Nexus 9516 Switch: All versions

Cisco Nexus 9000 Series Switches in ACI Mode: All versions

Cisco NX-OS: 12.3.1h - 13.1.2p

Cisco Nexus 9372PX-E Switch: All versions

Cisco Nexus 9348GC-FXP Switch: All versions

Cisco Nexus 93180YC-EX Switch: All versions

Cisco Nexus 93128TX Switch: All versions

Cisco Nexus 93180YC-FX Switch: All versions

Cisco Nexus 9364C Switch: All versions

Cisco Nexus 9372PX Switch: All versions

Cisco Nexus 93180LC-EX Switch: All versions

Cisco Nexus 9336PQ ACI Spine Switch: All versions

Cisco Nexus 9372TX Switch: All versions

Cisco Nexus 9336C-FX2 Switch: All versions

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External links
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190828-nexus-aci-dos

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.