Vulnerability Report

CVE-2021-27853

Title: Cisco Catalyst 3650-48Pd-L

Other

Proof Of Concept

No public PoC currently indexed for CVE-2021-27853.

CWE Category CWE-290
Published Date Sep 27, 2022
Modified Date Nov 04, 2025
Exploit Status Not Found
Score 4.7 CVSS v3.1
Exploit Probability (EPSS)
0.11%

Vulnerability Summary

CVE-2021-27853: 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.

Impacted Vendors

I
ieee 1
I
ietf 1
C
cisco 213

Reference Links

https://blog.champtar.fr/VLAN0_LLC_SNAP/ https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/ https://kb.cert.org/vuls/id/855201 https://standards.ieee.org/ieee/802.1Q/10323/ https://standards.ieee.org/ieee/802.2/1048/ https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-VU855201-J3z8CKTX https://blog.champtar.fr/VLAN0_LLC_SNAP/ https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/ https://kb.cert.org/vuls/id/855201 https://standards.ieee.org/ieee/802.1Q/10323/ https://standards.ieee.org/ieee/802.2/1048/ https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-VU855201-J3z8CKTX https://www.kb.cert.org/vuls/id/855201
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
4.7
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
CVSS v3.1
Source Entity 134c704f-9b21-4f2e-91b3-4a467353bcc0
Severity MEDIUM
4.7
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2021-27853 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector ADJACENT_NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Affected Stack

No specific products linked.