Denial of service in Cisco IOS and IOS XE Software

1) Missing Initialization of a Variable

EUVDB-ID: #VU56864

Risk: Low

CVSSv4.0: 4.6 [CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-34703

CWE-ID: CWE-456 - Missing Initialization of a Variable

Exploit availability: No

Description

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

The vulnerability exists due to improper initialization of a buffer in the Link Layer Discovery Protocol (LLDP) message parser. A remote authenticated attacker on the local network can trigger a reload of an affected device and cause a denial of service condition on the target system 

Mitigation

Install update from vendor's website.

Vulnerable software versions

Cisco IOS: 16.12.3

Cisco IOS XE: 16.12.3

CPE2.3

• cpe:2.3:o:cisco_systems:cisco_ios:16.12.3:*:*:*:*:*:*:*
• cpe:2.3:o:cisco_systems:cisco_ios_xe:16.12.3:*:*:*:*:*:*:*

External links

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lldp-dos-sBnuHSjT

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

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