Name: CVE-2021-27853: Authentication Bypass by Spoofing
Creator: Rapid7
Published: 2022-09-27T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2021-27853, CWE-290, CVSS 4.7, EPSS 0.00813

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 Details

CVSS 3.1 Base Score: 4.7
CVSS 3.1 Vector: (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Arista Eos	—	Upgrade to a remediated software version	Sep 4, 2024	Sep 27, 2022
Cisco Ios	—	Upgrade to the latest version of Cisco IOS to resolve this vulnerability	Jan 21, 2026	Sep 27, 2022
Cisco Nx Os	—	Upgrade to the latest version of Cisco NX-OS to resolve this vulnerability.	Jan 19, 2026	Sep 27, 2022
Cisco Xe	—	Upgrade to the latest version of Cisco IOS XE to resolve this vulnerability	Oct 17, 2025	Sep 27, 2022
Cisco Xr Os	—	Upgrade to the latest version of Cisco IOS-XR to resolve this vulnerability.	Sep 30, 2022	Sep 27, 2022

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CVSS Details

Covered by Rapid7

Prioritise with Active Threat Intelligence