Vulnerability Details : CVE-2021-27854
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.
Products affected by CVE-2021-27854
- cpe:2.3:a:ieee:ieee_802.2:*:*:*:*:*:*:*:*
- cpe:2.3:a:ietf:p802.1q:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-27854
0.07%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 32 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-27854
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
4.7
|
MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
2.8
|
1.4
|
NIST |
CWE ids for CVE-2021-27854
-
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.Assigned by:
- cret@cert.org (Secondary)
- nvd@nist.gov (Primary)
References for CVE-2021-27854
-
https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/
draft-ietf-v6ops-ra-guard-08 - IPv6 Router Advertisement GuardVendor Advisory
-
https://kb.cert.org/vuls/id/855201
VU#855201 - L2 network security controls can be bypassed using VLAN 0 stacking and/or 802.3 headers
-
https://blog.champtar.fr/VLAN0_LLC_SNAP/
Layer 2 network security bypass using VLAN 0, LLC/SNAP headers and invalid length | blog.champtar.fr
-
https://standards.ieee.org/ieee/802.1Q/10323/
IEEE SA - IEEE 802.1Q-2022Vendor Advisory
-
https://standards.ieee.org/ieee/802.2/1048/
IEEE SA - IEEE/ISO 802.2-1989Vendor Advisory
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