Description
A vulnerability in IPv6 traffic processing of Cisco IOS XE Wireless Controller Software for Cisco Catalyst 9000 Family Wireless Controllers could allow an unauthenticated, adjacent attacker to cause a Layer 2 (L2) loop in a configured VLAN, resulting in a denial of service (DoS) condition for that VLAN. The vulnerability is due to a logic error when processing specific link-local IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet that would flow inbound through the wired interface of an affected device. A successful exploit could allow the attacker to cause traffic drops in the affected VLAN, thus triggering the DoS condition.
Published: 2021-09-23
Score: 7.4 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Tracking

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Advisories
Source ID Title
EUVD EUVD EUVD-2021-21417 A vulnerability in IPv6 traffic processing of Cisco IOS XE Wireless Controller Software for Cisco Catalyst 9000 Family Wireless Controllers could allow an unauthenticated, adjacent attacker to cause a Layer 2 (L2) loop in a configured VLAN, resulting in a denial of service (DoS) condition for that VLAN. The vulnerability is due to a logic error when processing specific link-local IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet that would flow inbound through the wired interface of an affected device. A successful exploit could allow the attacker to cause traffic drops in the affected VLAN, thus triggering the DoS condition.
History

Thu, 30 Oct 2025 21:15:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:* cpe:2.3:o:cisco:ios_xe:-:*:*:*:*:*:*:*

Thu, 07 Nov 2024 22:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Subscriptions

Cisco Catalyst 9800 Catalyst 9800-40 Catalyst 9800-80 Catalyst 9800-cl Catalyst 9800-l Catalyst 9800-l-c Catalyst 9800-l-f Catalyst 9800 Embedded Wireless Controller Ios Xe
cve-icon MITRE

Status: PUBLISHED

Assigner: cisco

Published:

Updated: 2024-11-07T21:58:13.034Z

Reserved: 2021-06-15T00:00:00.000Z

Link: CVE-2021-34767

cve-icon Vulnrichment

Updated: 2024-08-04T00:19:48.133Z

cve-icon NVD

Status : Analyzed

Published: 2021-09-23T03:15:20.180

Modified: 2025-10-30T21:14:18.060

Link: CVE-2021-34767

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses