Vulnerability Monitor

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CVE-2021-27861

Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using LLC/SNAP headers with invalid length (and optionally VLAN0 headers)

Published

2022-09-27T19:15:09.330

Last Modified

2025-05-21T15:15:54.530

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 4.7 (MEDIUM)

Weaknesses

Type: Secondary
CWE-130
CWE-290
Type: Primary
CWE-290

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	ieee	ieee_802.2	≤ 802.2h-1997	Yes
Application	ietf	p802.1q	≤ d1.0	Yes

References

https://blog.champtar.fr/VLAN0_LLC_SNAP/ ([email protected])
https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/ Third Party Advisory ([email protected])
https://kb.cert.org/vuls/id/855201 ([email protected])
https://standards.ieee.org/ieee/802.1Q/10323/ Third Party Advisory ([email protected])
https://standards.ieee.org/ieee/802.2/1048/ Third Party Advisory ([email protected])
https://blog.champtar.fr/VLAN0_LLC_SNAP/ (af854a3a-2127-422b-91ae-364da2661108)
https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://kb.cert.org/vuls/id/855201 (af854a3a-2127-422b-91ae-364da2661108)
https://standards.ieee.org/ieee/802.1Q/10323/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://standards.ieee.org/ieee/802.2/1048/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)