Medium severity4.7NVD Advisory· Published Sep 27, 2022· Updated Jun 17, 2026
CVE-2021-27853
CVE-2021-27853
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
4- IEEE/802.2v5Range: 802.2h-1997
- IETF/draft-ietf-v6ops-ra-guardv5Range: 08
- IETF/P802.1Qv5Range: D1.0
Patches
Vulnerability mechanics
References
7- blog.champtar.fr/VLAN0_LLC_SNAP/nvdExploitThird Party Advisory
- datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/nvdTechnical DescriptionThird Party Advisory
- kb.cert.org/vuls/id/855201nvdThird Party AdvisoryUS Government Resource
- standards.ieee.org/ieee/802.1Q/10323/nvdVendor Advisory
- standards.ieee.org/ieee/802.2/1048/nvdVendor Advisory
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-VU855201-J3z8CKTXnvdThird Party Advisory
- www.kb.cert.org/vuls/id/855201nvd
News mentions
0No linked articles in our index yet.