CVE-2021-27854 L2 network filtering bypass using stacked VLAN0, LLC/SNAP headers, and Ethernet to Wifi frame translation
Attackers can bypass Layer 2 network filtering mechanisms like IPv6 RA guard by manipulating VLAN and LLC/SNAP headers during frame translation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-27854?
CVE-2021-27854 is a medium-severity vulnerability in IEEE 802.2, published on 27 Sep 2022. It can only be exploited from the same machine or local network, with no action from the victim.
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.
Weakness: CWE-290
Which versions are affected by CVE-2021-27854?
It affects 2 products.
Products include Ieee Ieee 802.2, Ietf P802.1q.
How do I fix CVE-2021-27854?
No fix has been published for CVE-2021-27854 yet. Limit exposure of the affected software until one is available.
Is CVE-2021-27854 being exploited?
There is no known exploitation of CVE-2021-27854 in the wild and no public exploit code.
Other vulnerabilities in IEEE 802.2
Sources
Also known as GHSA-433g-q37h-7crr.