Vulnerability Description
Layer 2 network filtering capabilities such as IPv6 RA guard or ARP inspection can be bypassed using combinations of VLAN 0 headers and LLC/SNAP 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 |
| Cisco | Catalyst 6503-E Firmware | 15.5\(01.01.85\)sy07 |
| Cisco | Catalyst 6503-E | - |
| Cisco | Catalyst 6504-E Firmware | 15.5\(01.01.85\)sy07 |
| Cisco | Catalyst 6504-E | - |
| Cisco | Catalyst 6506-E Firmware | 15.5\(01.01.85\)sy07 |
| Cisco | Catalyst 6506-E | - |
| Cisco | Catalyst 6509-E Firmware | 15.5\(01.01.85\)sy07 |
| Cisco | Catalyst 6509-E | - |
| Cisco | Catalyst 6509-Neb-A Firmware | 15.5\(01.01.85\)sy07 |
| Cisco | Catalyst 6509-Neb-A | - |
| Cisco | Catalyst 6509-V-E Firmware | 15.5\(01.01.85\)sy07 |
| Cisco | Catalyst 6509-V-E | - |
| Cisco | Catalyst 6513-E Firmware | 15.5\(01.01.85\)sy07 |
| Cisco | Catalyst 6513-E | - |
| Cisco | Catalyst 6807-Xl Firmware | 15.5\(01.01.85\)sy07 |
| Cisco | Catalyst 6807-Xl | - |
| Cisco | Catalyst 6840-X Firmware | 15.5\(01.01.85\)sy07 |
| Cisco | Catalyst 6840-X | - |
Related Weaknesses (CWE)
References
- https://blog.champtar.fr/VLAN0_LLC_SNAP/ExploitThird Party Advisory
- https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/Technical DescriptionThird Party Advisory
- https://kb.cert.org/vuls/id/855201Third Party AdvisoryUS Government Resource
- https://standards.ieee.org/ieee/802.1Q/10323/Vendor Advisory
- https://standards.ieee.org/ieee/802.2/1048/Vendor Advisory
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-VThird Party Advisory
- https://blog.champtar.fr/VLAN0_LLC_SNAP/ExploitThird Party Advisory
- https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/Technical DescriptionThird Party Advisory
- https://kb.cert.org/vuls/id/855201Third Party AdvisoryUS Government Resource
- https://standards.ieee.org/ieee/802.1Q/10323/Vendor Advisory
- https://standards.ieee.org/ieee/802.2/1048/Vendor Advisory
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-VThird Party Advisory
- https://www.kb.cert.org/vuls/id/855201
FAQ
What is CVE-2021-27853?
CVE-2021-27853 is a vulnerability with a CVSS score of 4.7 (MEDIUM). Layer 2 network filtering capabilities such as IPv6 RA guard or ARP inspection can be bypassed using combinations of VLAN 0 headers and LLC/SNAP headers.
How severe is CVE-2021-27853?
CVE-2021-27853 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-2021-27853?
Check the references section above for vendor advisories and patch information. Affected products include: Ieee Ieee 802.2, Ietf P802.1Q, Cisco Catalyst 6503-E Firmware, Cisco Catalyst 6503-E, Cisco Catalyst 6504-E Firmware.