VulnerabilityModified
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)
MEDIUM 4.7EPSS 0.62%
Does this matter?
Lower severity and a low EPSS score (0.62%). Track it; it rarely justifies an emergency change on its own.
Description
Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using LLC/SNAP headers with invalid length (and optionally VLAN0 headers)
- CVSS 3.1
- 4.7 MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
- EPSS
- 0.62% probability · 48th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-130, CWE-290
- Affected
- ieee/ieee 802.2 · ietf/p802.1q
- Source
- cret@cert.org
References
- https://blog.champtar.fr/VLAN0_LLC_SNAP/
- https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/Third Party Advisory
- https://kb.cert.org/vuls/id/855201
- https://standards.ieee.org/ieee/802.1Q/10323/Third Party Advisory
- https://standards.ieee.org/ieee/802.2/1048/Third Party Advisory
- https://blog.champtar.fr/VLAN0_LLC_SNAP/
- https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/Third Party Advisory
- https://kb.cert.org/vuls/id/855201
- https://standards.ieee.org/ieee/802.1Q/10323/Third Party Advisory
- https://standards.ieee.org/ieee/802.2/1048/Third Party Advisory
- https://www.kb.cert.org/vuls/id/855201
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.