CVE-2021-27854
kernel: layer 2 network filtering capabilities bypass / wifi
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · September 27, 2021
Updated · November 21, 2025
Description
Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using combinations of VLAN 0 headers, LLC/SNAP headers and Ethernet to Wifi frame translation.
Statement
Red Hat deems this to be a configuration issue. There is no vulnerability in the Linux kernel itself, there is a lot of ways to misuse the filtering facilities provided by the kernel and do insecure filtering rules, but you also have everything to actually set up secure rules.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CWE not specified