Vulnerability · Published Sep 27, 2022 · Assigned by certcc

CVE-2021-27854L2 network filtering bypass using stacked VLAN0, LLC/SNAP headers, and Ethernet to Wifi frame translation

Medium 4.7

In plain English

A medium-severity authentication bypass by spoofing in 802.2 from IEEE. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 54% of all known vulnerabilities).

Severity (CVSS 3.1)4.7Medium
Exploit odds (30 days)0.7%top 46.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using combinations of VLAN 0 headers, LLC/SNAP headers, and converting frames from Ethernet to Wifi and its reverse.

Affected products (as reported)

VendorProductVersions
IETF P802.1Q D1.0 – through D1.0
IETF draft-ietf-v6ops-ra-guard 08 – through 08
IEEE 802.2 802.2h-1997 – through 802.2h-1997

Weakness: CWE-290 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

References