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Status published
Unknown
CVE-2021-27854
L2 network filtering bypass using stacked VLAN0, LLC/SNAP headers, and Ethernet to Wifi frame translation
Vulnerability Description
Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using combinations of VLAN 0 headers, LLC/SNAP headers, and converting frames from Ethernet to Wifi and its reverse.
Impact Analysis
Refer to official advisory for detailed impact metrics.
Remediation
Ensure systems are updated to the latest vendor-supplied patch levels.
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Credits & Attribution
The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:
- Etienne Champetier (@champtar) <champetier.etienne@gmail.com>
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Affected Vendor
IETF
View all reports →Affected Software
P802.1Q, draft-ietf-v6ops-ra-guard, 802.2
Vulnerable Versions:
D1.0, 08, 802.2h-1997
Timeline
Official Publish:
September 27th, 2022
Last Modified:
November 4th, 2025
Added to House:
July 21st, 2026
CVSS Vectors
No vector data available