A vulnerability in the Protocol Independent Multicast Version 6 (PIM6) feature of Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an authenticated, low-privileged, remote attacker to trigger a crash of the PIM6 process, resulting in a denial of service (DoS) condition.
This vulnerability is due to improper processing of PIM6 ephemeral data queries. An attacker could exploit this vulnerability by sending a crafted ephemeral query to an affected device through one of the following methods: NX-API REST, NETCONF, RESTConf, gRPC, or Model Driven Telemetry. A successful exploit could allow the attacker to cause the PIM6 process to crash and restart, causing potential adjacency flaps and resulting in a DoS of the PIM6 and ephemeral query processes.
For an example of an ephemeral query, see the About Ephemeral Data in gRPC section of the Cisco Nexus 9000 Series NX-OS Programmability Guide, Release 9.3(x).
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-nxospc-pim6-vG4jFPh
This advisory is part of the August 2025 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2025 Semiannual Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.
Security Impact Rating: Medium
CVE: CVE-2025-20262
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