Security Bulletin
This security bulletin contains one medium risk vulnerability.
EUVDB-ID: #VU56875
Risk: Medium
CVSSv3.1: 6.4 [CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-34714
CWE-ID:
CWE-20 - Improper input validation
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to insufficient validation of user-supplied input in the Unidirectional Link Detection (UDLD) feature. A remote attacker on the local network can pass specially crafted input to the application and perform a denial of service (DoS) attack.
MitigationInstall updates from vendor's website.
Vulnerable software versionsCisco FXOS: 2.2 - 2.9
Cisco IOS: 16.12.4
Cisco IOS XE: 16.12.4
Cisco IOS XR: 6.6 - 7.4
Cisco NX-OS: 7.0.3 I7.9
Cisco UCS: 4.0 - 4.2
Cisco Firepower 4100 Series Next-Generation Firewall: All versions
Cisco Firepower 9300 Security Appliance: All versions
Cisco MDS 9000 Series Multilayer Switches: All versions
Cisco Nexus 3000 Series Switches: All versions
Nexus 5500 Platform Switches: All versions
Nexus 5600 Platform Switches: All versions
Cisco Nexus 6000 Series Switches: All versions
Cisco Nexus 7000 Series Switches: All versions
Cisco Nexus 9000 Series Switches NX-OS Mode: All versions
UCS 6200 Series Fabric Interconnects: All versions
UCS 6300 Series Fabric Interconnects: All versions
UCS 6400 Series Fabric Interconnects: All versions
External linksQ & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.