Denial of service in Cisco IOS XE Software for Catalyst 9800 Series Wireless Controllers

1) Always-Incorrect Control Flow Implementation

EUVDB-ID: #VU56859

Risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-34767

CWE-ID: CWE-670 - Always-Incorrect Control Flow Implementation

Exploit availability: No

Description

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

The vulnerability exists due to a logic error when processing specific link-local IPv6 traffic. A remote attacker on the local network can send a specially crafted IPv6 packet and cause a denial of service condition on the target system.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Cisco IOS XE: All versions

Cisco Catalyst 9800 Wireless Controller: All versions

Catalyst 9800 Wireless Controllers for Cloud: All versions

CPE2.3

• cpe:2.3:o:cisco_systems:cisco_ios_xe:*:*:*:*:*:*:*:*
• cpe:2.3:h:cisco_systems:cisco_catalyst_9800_wireless_controller:*:*:*:*:*:*:*:*
• cpe:2.3:a:cisco_systems:catalyst_9800_wireless_controllers_for_cloud:*:*:*:*:*:*:*:*

External links

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ewlc-ipv6-dos-NMYeCnZv

Q & 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.