CVE-2021-34703: cisco cisco_ios Missing Initialization of a Variable

Vulnerability summary

CVE-2021-34703 is a medium (CVSS 6.8) Missing Initialization of a Variable vulnerability in cisco cisco_ios. EPSS estimates a 1.19% chance of exploitation in the next 30 days, higher than 67.3% of scored vulnerabilities.

Timeline

1. 23-09-2021
   PublishedVulnerability first disclosed.
2. 07-11-2024
   Last modifiedVulnerability information updated.

Description

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.

• CWE-456Missing Initialization of a VariableThe product does not initialize critical variables, which causes the execution environment to use unexpected values.
• CWE-665Improper InitializationThe product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.