CVE-2021-27862

low-risk
Published 2022-09-27

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).

Do I need to act?

-
0.09% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
4
CVSS 4.7/10 Medium
ADJACENT_NETWORK / LOW complexity

Affected Products (2)

Ieee 802.2
P802.1Q

Affected Vendors

Ieee Ietf

References (9)

https://blog.champtar.fr/VLAN0_LLC_SNAP/
Vendor Advisory https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/
https://kb.cert.org/vuls/id/855201
Vendor Advisory https://standards.ieee.org/ieee/802.2/1048/
https://blog.champtar.fr/VLAN0_LLC_SNAP/
Vendor Advisory https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/
https://kb.cert.org/vuls/id/855201
Vendor Advisory https://standards.ieee.org/ieee/802.2/1048/
https://www.kb.cert.org/vuls/id/855201
23
/ 100
low-risk
Severity 16/34 · Moderate
Exploitability 0/34 · Minimal
Exposure 7/34 · Low