CVE-2021-27862: L2 network filtering bypass using stacked VLAN0 and LLC/SNAP headers with an invalid length during Ethernet to Wifi frame translation
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).
Affected Software
Event History
Frequently Asked Questions
What is the vulnerability ID for this vulnerability?
The vulnerability ID for this vulnerability is CVE-2021-27862.
What is the severity of CVE-2021-27862?
The severity of CVE-2021-27862 is medium with a severity value of 4.7.
What is the affected software in CVE-2021-27862?
The affected software in CVE-2021-27862 includes IEEE 802.2 up to and including version 802.2h-1997, and IETF P802.1q up to and including version d1.0.
How can Layer 2 network filtering capabilities be bypassed in CVE-2021-27862?
Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed in CVE-2021-27862 using LLC/SNAP headers with invalid length and Ethernet to WiFi frame conversion, and optionally VLAN0 headers.
Are there any references for CVE-2021-27862?
Yes, there are references available for CVE-2021-27862. They include: [1] https://blog.champtar.fr/VLAN0_LLC_SNAP/, [2] https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/, [3] https://kb.cert.org/vuls/id/855201