CVE-2026-73439

Summary

On affected platforms running Arista EOS, if OpenConfig is configured and running a gNMI server on the system, and if gNSI Pathz is configured and a gNSI Pathz policy is present on the system, then gNMI may fail to correctly enforce the rules in this policy if both a group rule and a user rule for the same path is present in the policy. Under certain conditions, this can lead to an authenticated user gaining unauthorized permission to read or write gNMI paths that the Pathz policy is intended to restrict.

Affected Software

VendorProductVersion RangeStatus
Arista NetworksEOS4.33.2F <= 4.33.8Maffected
Arista NetworksEOS4.34.0F <= 4.34.6Maffected
Arista NetworksEOS4.35.0F <= 4.35.5Maffected
Arista NetworksEOS4.36.0F <= 4.36.0.1Faffected

Weaknesses

  • CWE-842: CWE-842 Placement of User into Incorrect Group

Workarounds

Option 1: Disable gNSI Pathz entirely:

switch#configure switch(config)#management api gnsi switch(config-mgmt-api-gnsi)#no service pathz

Option 2: Push a new gNSI Pathz policy that does not contain any group rules, using only user-principal rules. To push a new policy via grpcurl:

grpcurl -protoset ./pathz.proto.pb -H 'username:$USER' -v -d @ -plaintext $TARGET:$PORT gnsi.pathz.v1.Pathz/Rotate << EOF { "upload_request": { "version": "<version>", "created_on": <timestamp>, "policy": <policy> } } { "finalize_rotation": {} } EOF

Ensure all rules in the policy use "user" as the principal rather than "group" to avoid triggering this vulnerability.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: total

References