---
cve: "CVE-2021-27853"
severity: "MEDIUM"
cvss: 4.7
epss: "71%"
vendor: "IETF"
kev: false
exploited: false
published: "2022-09-27 17:55:09"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-19T16:36:32+02:00"
---

# CVE-2021-27853

> 4.7 MEDIUM

## Beschreibung

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-Vektor

```
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Benachbart | warn |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Keine | good |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Keine | good |

## Referenzen

- <https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/>
- <https://standards.ieee.org/ieee/802.2/1048/>
- <https://standards.ieee.org/ieee/802.1Q/10323/>
- <https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-VU855201-J3z8CKTX>
- <https://kb.cert.org/vuls/id/855201>
- <https://blog.champtar.fr/VLAN0_LLC_SNAP/>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2021-27853) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_