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Status published
Unknown
CVE-2021-27861
L2 network filtering bypass using stacked VLAN0 and LLC/SNAP headers with invalid lengths
Vulnerability Description
Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using LLC/SNAP headers with invalid length (and optionally VLAN0 headers)
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>
References
More from IEEE
View All →CVE-2021-27862
L2 network filtering bypass using stacked VLAN0 and LLC/SNAP headers with an invalid length during Ethernet to Wifi frame translation
Unknown
0
CVE-2021-27853
L2 network filtering can be bypassed using stacked VLAN0 and LLC/SNAP headers
Unknown
0
CVE-2017-13097
The P1735 IEEE standard describes flawed methods for encrypting electronic-design intellectual property (IP), including modification of Rights Block to remove or relax license requirement
High
7.8
CVE-2017-13096
The P1735 IEEE standard describes flawed methods for encrypting electronic-design intellectual property (IP), including modification of Rights Block to remove or relax access control
High
7.8
CVE-2017-13095
The P1735 IEEE standard describes flawed methods for encrypting electronic-design intellectual property (IP), including modification of a license-deny response to a license grant
High
7.8
Affected Vendor
IEEE
View all reports →Affected Software
802.2, draft-ietf-v6ops-ra-guard, P802.1Q
Vulnerable Versions:
802.2h-1997, 08, D1.0
Timeline
Official Publish:
September 27th, 2022
Last Modified:
November 4th, 2025
Added to House:
July 21st, 2026
CVSS Vectors
No vector data available