---
cve: "CVE-2021-27862"
severity: "MEDIUM"
cvss: 4.7
epss: "64%"
vendor: "IETF"
kev: false
exploited: false
published: "2022-09-27 19:15:09"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-19T03:42:22+02:00"
---

# CVE-2021-27862

> 4.7 MEDIUM

## Beschreibung

Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using LLC/SNAP headers with invalid length and Ethernet to Wifi frame conversion (and optionally VLAN0 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://kb.cert.org/vuls/id/855201>
- <https://blog.champtar.fr/VLAN0_LLC_SNAP/>
- <https://www.kb.cert.org/vuls/id/855201>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2021-27862) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_