Vulnerability 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 Score
4.7
MEDIUM
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Ieee | Ieee 802.2 | <= 802.2h-1997 |
| Ietf | P802.1Q | <= d1.0 |
Related Weaknesses (CWE)
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
FAQ
What is CVE-2021-27861?
CVE-2021-27861 is a vulnerability with a CVSS score of 4.7 (MEDIUM). Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using LLC/SNAP headers with invalid length (and optionally VLAN0 headers)
How severe is CVE-2021-27861?
CVE-2021-27861 has been rated MEDIUM with a CVSS base score of 4.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-27861?
Check the references section above for vendor advisories and patch information. Affected products include: Ieee Ieee 802.2, Ietf P802.1Q.