Unauthenticated OS command injection in Arista VeloCloud Orchestrator On-Prem gives full host compromise (CVE-2026-16812)
Arista's advisory states the flaw was discovered externally and is known to be actively exploited, and BleepingComputer's 2026-09-23 report on a newer VeloCloud Orchestrator zero-day recalls this one as a flaw Arista patched in July; an orchestrator left below the fixed versions is an unauthenticated route to the entire SD-WAN fabric it controls.
Functionality intended for internal use only in VeloCloud Orchestrator (VCO) On-Prem is reachable remotely without authentication and allows OS command injection on the VCO host. An attacker gains control of the orchestrator and the configuration and data of every SD-WAN edge it manages.
Affected: Arista VeloCloud Orchestrator On-Prem >= 5.2.0 < 5.2.3.14; Arista VeloCloud Orchestrator On-Prem >= 6.1.0 < 6.1.3.4; Arista VeloCloud Orchestrator On-Prem >= 6.4.0 < 6.4.2.4; Arista VeloCloud Orchestrator On-Prem >= 7.0.0 < 7.0.0.1; VeloCloud Orchestrator Hosted (patched by Arista)
How to Test
Check the VCO release against the affected list: 5.2.x below 5.2.3.14, 6.1.x below 6.1.3.4, 6.4.x below 6.4.2.4 and 7.0.x below 7.0.0.1 are vulnerable; Arista notes end-of-support versions have not been assessed and should be treated as exposed. Arista provides a CSAF JSON file with the advisory for automated version matching. Review VCO web access logs for requests to internal-only functionality from external addresses, and inspect the VCO host for unexpected processes, accounts, cron entries or outbound connections.
How to Patch
Upgrade VCO On-Prem to 5.2.3.14, 6.1.3.4, 6.4.2.4 or 7.0.0.1 (or later in each train). Hosted and Dedicated VCO instances are being patched by Arista. Until the upgrade is applied, restrict network access to the orchestrator so it is reachable only from trusted management addresses and the SD-WAN edges that need it.