Cisco Advance Notification for Publication of October 7, 2026, Security Advisories
cisco-sa-notice-fBn58ELx
Advisory summary
A vulnerability in the endpoint group (EPG) contract functionality of Cisco Nexus 9000 Series Fabric Switches in ACI Mode could allow an unauthenticated, remote attacker to bypass configured EPG contracts. This vulnerability is due to an improper control with EPG contracts. An attacker could exploit this vulnerability by sending IPv4 or IPv6 packets using UDP source and destination ports that are assigned to DHCP traffic through an affected device.
A successful exploit could allow the attacker to bypass EPG contracts on the affected device. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-aci-epgcbp-SfDU7NLf This advisory is part of a group of advisories.
For a complete list of the advisories and links to them, see Cisco Advance Notification for Publication of October 7, 2026, Security Advisories. In addition, for further documentation of improvements and fixes in Cisco NX-OS Software, see Cisco NX-OS Software Security Hardening Release: October 2026.
Security Impact Rating: Medium CVE: CVE-2026-20038
Scope
What the vendor says is affected
The collected bulletin did not provide a separate affected-products list. Check the original bulletin before making an exposure decision.
Next step
What the vendor recommends
Cisco has released software updates that address this vulnerability.
Review the complete instructions on the vendor's siteTimeline
When this advisory changed
- Published by Cisco
The publication date reported by the vendor.
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Vulnerabilities