CVE-2021-27854 - Vulnerability Details - OpenCVE

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.

No CVSS v4.0

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable no

Technical Impact partial

Vendors	Products
Ieee	Ieee 802.2
Ietf	P802.1q

Configuration 1 [-]

cpe:2.3:a:ieee:ieee_802.2:*:*:*:*:*:*:*:*

Configuration 2 [-]

cpe:2.3:a:ietf:p802.1q:*:*:*:*:*:*:*:*

No data.

References

Link	Providers
https://blog.champtar.fr/VLAN0_LLC_SNAP/
https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/
https://kb.cert.org/vuls/id/855201
https://nvd.nist.gov/vuln/detail/CVE-2021-27854
https://standards.ieee.org/ieee/802.1Q/10323/
https://standards.ieee.org/ieee/802.2/1048/
https://www.cve.org/CVERecord?id=CVE-2021-27854
https://www.kb.cert.org/vuls/id/855201

History

Tue, 04 Nov 2025 20:30:00 +0000

Type	Values Removed	Values Added
References		https://www.kb.cert.org/vuls/id/855201

Wed, 21 May 2025 16:15:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

MITRE

Status: PUBLISHED

Assigner: certcc

Published: 2022-09-27T18:40:12.738Z

Updated: 2025-11-04T19:12:26.598Z

Reserved: 2021-03-01T00:00:00.000Z

Link: CVE-2021-27854

Vulnrichment

Updated: 2025-11-04T19:12:26.598Z

NVD

Status : Modified

Published: 2022-09-27T19:15:09.240

Modified: 2025-11-04T20:15:59.750

Link: CVE-2021-27854

Redhat

Severity : Moderate

Publid Date: 2021-09-27T10:30:00Z

Links: CVE-2021-27854 - Bugzilla

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