medium
6.8
CWE
665 456
Advisory Published
Updated

CVE-2021-34703: Cisco IOS and IOS XE Software Link Layer Discovery Protocol Denial of Service Vulnerability

First published: Thu Sep 23 2021(Updated: )

A vulnerability in the Link Layer Discovery Protocol (LLDP) message parser of Cisco IOS Software and Cisco IOS XE Software could allow an attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to improper initialization of a buffer. An attacker could exploit this vulnerability via any of the following methods: An authenticated, remote attacker could access the LLDP neighbor table via either the CLI or SNMP while the device is in a specific state. An unauthenticated, adjacent attacker could corrupt the LLDP neighbor table by injecting specific LLDP frames into the network and then waiting for an administrator of the device or a network management system (NMS) managing the device to retrieve the LLDP neighbor table of the device via either the CLI or SNMP. An authenticated, adjacent attacker with SNMP read-only credentials or low privileges on the device CLI could corrupt the LLDP neighbor table by injecting specific LLDP frames into the network and then accessing the LLDP neighbor table via either the CLI or SNMP. A successful exploit could allow the attacker to cause the affected device to crash, resulting in a reload of the device.

Credit: ykramarz@cisco.com

Affected SoftwareAffected VersionHow to fix
Cisco IOS<=16.12.3
Cisco IOS XE<=16.12.3
Cisco 1000 Integrated Services Router
Cisco 1100-4g\/6g Integrated Services Router
Cisco 1100-4p Integrated Services Router
Cisco 1100-8p Integrated Services Router
Cisco 1100 Integrated Services Router
Cisco 1101-4p Integrated Services Router
Cisco 1101 Integrated Services Router
Cisco 1109-2p Integrated Services Router
Cisco 1109-4p Integrated Services Router
Cisco 1109 Integrated Services Router
Cisco 1111x-8p Integrated Services Router
Cisco 1111x Integrated Services Router
Cisco 111x Integrated Services Router
Cisco 1120 Integrated Services Router
Cisco 1160 Integrated Services Router
Cisco 4000 Integrated Services Router
Cisco 4221 Integrated Services Router
Cisco 4321 Integrated Services Router
Cisco 4331 Integrated Services Router
Cisco 4351 Integrated Services Router
Cisco 4431 Integrated Services Router
Cisco 4451-x Integrated Services Router
Cisco 4451 Integrated Services Router
Cisco 4461 Integrated Services Router
Cisco Catalyst 3650-12x48fd-e
Cisco Catalyst 3650-12x48fd-l
Cisco Catalyst 3650-12x48fd-s
Cisco Catalyst 3650-12x48uq
Cisco Catalyst 3650-12x48uq-e
Cisco Catalyst 3650-12x48uq-l
Cisco Catalyst 3650-12x48uq-s
Cisco Catalyst 3650-12x48ur
Cisco Catalyst 3650-12x48ur-e
Cisco Catalyst 3650-12x48ur-l
Cisco Catalyst 3650-12x48ur-s
Cisco Catalyst 3650-12x48uz
Cisco Catalyst 3650-12x48uz-e
Cisco Catalyst 3650-12x48uz-l
Cisco Catalyst 3650-12x48uz-s
Cisco Catalyst 3650-24pd
Cisco Catalyst 3650-24pd-e
Cisco Catalyst 3650-24pd-l
Cisco Catalyst 3650-24pd-s
Cisco Catalyst 3650-24pdm
Cisco Catalyst 3650-24pdm-e
Cisco Catalyst 3650-24pdm-l
Cisco Catalyst 3650-24pdm-s
Cisco Catalyst 3650-24ps-e
Cisco Catalyst 3650-24ps-l
Cisco Catalyst 3650-24ps-s
Cisco Catalyst 3650-24td-e
Cisco Catalyst 3650-24td-l
Cisco Catalyst 3650-24td-s
Cisco Catalyst 3650-24ts-e
Cisco Catalyst 3650-24ts-l
Cisco Catalyst 3650-24ts-s
Cisco Catalyst 3650-48fd-e
Cisco Catalyst 3650-48fd-l
Cisco Catalyst 3650-48fd-s
Cisco Catalyst 3650-48fq
Cisco Catalyst 3650-48fq-e
Cisco Catalyst 3650-48fq-l
Cisco Catalyst 3650-48fq-s
Cisco Catalyst 3650-48fqm
Cisco Catalyst 3650-48fqm-e
Cisco Catalyst 3650-48fqm-l
Cisco Catalyst 3650-48fqm-s
Cisco Catalyst 3650-48fs-e
Cisco Catalyst 3650-48fs-l
Cisco Catalyst 3650-48fs-s
Cisco Catalyst 3650-48pd-e
Cisco Catalyst 3650-48pd-l
Cisco Catalyst 3650-48pd-s
Cisco Catalyst 3650-48pq-e
Cisco Catalyst 3650-48pq-l
Cisco Catalyst 3650-48pq-s
Cisco Catalyst 3650-48ps-e
Cisco Catalyst 3650-48ps-l
Cisco Catalyst 3650-48ps-s
Cisco Catalyst 3650-48td-e
Cisco Catalyst 3650-48td-l
Cisco Catalyst 3650-48td-s
Cisco Catalyst 3650-48tq-e
Cisco Catalyst 3650-48tq-l
Cisco Catalyst 3650-48tq-s
Cisco Catalyst 3650-48ts-e
Cisco Catalyst 3650-48ts-l
Cisco Catalyst 3650-48ts-s
Cisco Catalyst 3650-8x24pd-e
Cisco Catalyst 3650-8x24pd-l
Cisco Catalyst 3650-8x24pd-s
Cisco Catalyst 3650-8x24uq
Cisco Catalyst 3650-8x24uq-e
Cisco Catalyst 3650-8x24uq-l
Cisco Catalyst 3650-8x24uq-s
Cisco Catalyst 3850
Cisco Catalyst 3850-12s-e
Cisco Catalyst 3850-12s-s
Cisco Catalyst 3850-12x48u
Cisco Catalyst 3850-12xs-e
Cisco Catalyst 3850-12xs-s
Cisco Catalyst 3850-16xs-e
Cisco Catalyst 3850-16xs-s
Cisco Catalyst 3850-24p-e
Cisco Catalyst 3850-24p-l
Cisco Catalyst 3850-24p-s
Cisco Catalyst 3850-24pw-s
Cisco Catalyst 3850-24s-e
Cisco Catalyst 3850-24s-s
Cisco Catalyst 3850-24t-e
Cisco Catalyst 3850-24t-l
Cisco Catalyst 3850-24t-s
Cisco Catalyst 3850-24u
Cisco Catalyst 3850-24u-e
Cisco Catalyst 3850-24u-l
Cisco Catalyst 3850-24u-s
Cisco Catalyst 3850-24xs
Cisco Catalyst 3850-24xs-e
Cisco Catalyst 3850-24xs-s
Cisco Catalyst 3850-24xu
Cisco Catalyst 3850-24xu-e
Cisco Catalyst 3850-24xu-l
Cisco Catalyst 3850-24xu-s
Cisco Catalyst 3850-32xs-e
Cisco Catalyst 3850-32xs-s
Cisco Catalyst 3850-48f-e
Cisco Catalyst 3850-48f-l
Cisco Catalyst 3850-48f-s
Cisco Catalyst 3850-48p-e
Cisco Catalyst 3850-48p-l
Cisco Catalyst 3850-48p-s
Cisco Catalyst 3850-48pw-s
Cisco Catalyst 3850-48t-e
Cisco Catalyst 3850-48t-l
Cisco Catalyst 3850-48t-s
Cisco Catalyst 3850-48u
Cisco Catalyst 3850-48u-e
Cisco Catalyst 3850-48u-l
Cisco Catalyst 3850-48u-s
Cisco Catalyst 3850-48xs
Cisco Catalyst 3850-48xs-e
Cisco Catalyst 3850-48xs-f-e
Cisco Catalyst 3850-48xs-f-s
Cisco Catalyst 3850-48xs-s
Cisco Catalyst 3850-nm-2-40g
Cisco Catalyst 3850-nm-8-10g
Cisco Catalyst 9200
Cisco Catalyst 9300
Cisco Catalyst 9300-24p-a
Cisco Catalyst 9300-24p-e
Cisco Catalyst 9300-24s-a
Cisco Catalyst 9300-24s-e
Cisco Catalyst 9300-24t-a
Cisco Catalyst 9300-24t-e
Cisco Catalyst 9300-24u-a
Cisco Catalyst 9300-24u-e
Cisco Catalyst 9300-24ux-a
Cisco Catalyst 9300-24ux-e
Cisco Catalyst 9300-48p-a
Cisco Catalyst 9300-48p-e
Cisco Catalyst 9300-48s-a
Cisco Catalyst 9300-48s-e
Cisco Catalyst 9300-48t-a
Cisco Catalyst 9300-48t-e
Cisco Catalyst 9300-48u-a
Cisco Catalyst 9300-48u-e
Cisco Catalyst 9300-48un-a
Cisco Catalyst 9300-48un-e
Cisco Catalyst 9300-48uxm-a
Cisco Catalyst 9300-48uxm-e
Cisco Catalyst 9300l
Cisco Catalyst 9300l-24p-4g-a
Cisco Catalyst 9300l-24p-4g-e
Cisco Catalyst 9300l-24p-4x-a
Cisco Catalyst 9300l-24p-4x-e
Cisco Catalyst 9300l-24t-4g-a
Cisco Catalyst 9300l-24t-4g-e
Cisco Catalyst 9300l-24t-4x-a
Cisco Catalyst 9300l-24t-4x-e
Cisco Catalyst 9300l-48p-4g-a
Cisco Catalyst 9300l-48p-4g-e
Cisco Catalyst 9300l-48p-4x-a
Cisco Catalyst 9300l-48p-4x-e
Cisco Catalyst 9300l-48t-4g-a
Cisco Catalyst 9300l-48t-4g-e
Cisco Catalyst 9300l-48t-4x-a
Cisco Catalyst 9300l-48t-4x-e
Cisco Catalyst 9300l Stack
Cisco Catalyst 9400
Cisco Catalyst 9407r
Cisco Catalyst 9410r
Cisco Catalyst 9500
Cisco Catalyst 9600
Cisco Catalyst 9800
Cisco Catalyst 9800-40
Cisco Catalyst 9800-80
Cisco Catalyst 9800-cl
Cisco Catalyst 9800-l
Cisco Catalyst 9800-l-c
Cisco Catalyst 9800-l-f
Cisco Csr 1000v

Never miss a vulnerability like this again

Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.

Read MoreStart Free Trial

Reference Links

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2024 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203