Home/CVE/A vulnerability in the EtherChannel port subscription logic of Cisco Nexus 9500 Series Switches could allow an unauthent
CVE

CVE-2021-1591

A vulnerability in the EtherChannel port subscription logic of Cisco Nexus 9500 Series Switches could allow an unauthent

A vulnerability in the EtherChannel port subscription logic of Cisco Nexus 9500 Series Switches could allow an unauthenticated, remote attacker to bypass access control list (ACL) rules that are configured on an affected device. This vulnerability is due to oversubscription of resources that occurs when applying ACLs to port channel interfaces. An attacker could exploit this vulnerability by attempting to access network resources that are protected by the ACL.

A successful exploit could allow the attacker to access network resources that would be protected by the ACL that was applied on the port channel interface.

MEDIUM · CVSS 5.8 EPSS 0.00293
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  • SSVC automatable: yes - attacks can be scripted at scale
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-284Improper Access Control
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Affected Products & Versions

1
cisco nx-osall versions
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Scoring & Timeline

5.8
MEDIUM · CVSS v3.1 · psirt@cisco.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD25 Aug 2021 · 08:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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Vendor Advisories

1
cisco-csafcisco-sa-nexus-acl-vrvQYPVe
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nexus-acl-vrvQYPVePatchVendor Advisory
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