cve/2021/CVE-2021-27853.md

### [CVE-2021-27853](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27853)
![](https://img.shields.io/static/v1?label=Product&message=802.2&color=blue)
![](https://img.shields.io/static/v1?label=Product&message=P802.1Q&color=blue)
![](https://img.shields.io/static/v1?label=Product&message=draft-ietf-v6ops-ra-guard&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=08%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=802.2h-1997%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=D1.0%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-290%3A%20Authentication%20Bypass%20by%20Spoofing&color=brightgreen)

### 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.

### POC

#### Reference
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-VU855201-J3z8CKTX

#### Github
No PoCs found on GitHub currently.