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CVE-2021-27862

L2 network filtering bypass using stacked VLAN0 and LLC/SNAP headers with an invalid length during Ethernet to Wifi frame translation

Published: Sep 27, 2022Updated: Nov 4, 2025 Sources: CVE List NVDCWE-130
NVD MITRE
4.7CVSSMEDIUM
EPSS Score
0.6%
Top 54.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using LLC/SNAP headers with invalid length and Ethernet to Wifi frame conversion (and optionally VLAN0 headers).

CVSS Vector Breakdown

AV:AAC:LPR:NUI:NS:CC:NI:LA:N
Exploitability
AV:AAttack Vector
Adjacent
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:NConfidentiality
None
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-130CWE-290

Affected Products

802.2IEEE
draft-ietf-v6ops-ra-guard-08IETF
ieee 802.2ieee
p802.1qietf

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Initial Access
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References

https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/
datatracker.ietf.org
https://standards.ieee.org/ieee/802.2/1048/
standards.ieee.org
https://kb.cert.org/vuls/id/855201
kb.cert.org
and 2 more references View all →

Timeline

Published
Sep 27, 2022
Last Updated
Nov 4, 2025

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