CVE-2021-34703
6.8 · MEDIUMOverview
CVE-2021-34703 is a medium-severity vulnerability affecting cisco ios. It was published on September 23, 2021 and has a CVSS 3.1 base score of 6.8 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.8, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical 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 specifi
Remediation
Check the references section for vendor advisories and patches from cisco. Update ios to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| cisco | ios | 0 | Affected |
| cisco | ios_xe | 0 | Affected |
Frequently Asked Questions
What is CVE-2021-34703?
CVE-2021-34703 is a medium-severity vulnerability affecting cisco ios. It was published on September 23, 2021 and has a CVSS 3.1 base score of 6.8 (MEDIUM).
How severe is CVE-2021-34703?
This vulnerability has a CVSS 3.1 base score of 6.8, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2021-34703?
Check the references section for vendor advisories and patches from cisco. Update ios to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-34703?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-34703 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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