CVE-2021-27854

4.7 mediumEPSS 0.7%

Medium (4.7). EPSS 0.7% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

4.7 medium

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

EPSS: 0.7% chance of exploitation in the next 30 days; higher than 53% of CVEs (scores of 2026-10-31)
CWE: CWE-290
Published: 2022-09-27
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

ieee:ieee_802.2
ietf:p802.1q

References

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://standards.ieee.org/ieee/802.1Q/10323/
https://standards.ieee.org/ieee/802.2/1048/

Check your stack JSON