Arista patches actively exploited VeloCloud Orchestrator zero-day

Arista Networks has released security patches for a zero-day flaw that is being actively exploited and affects VeloCloud Orchestrator (VCO) On-Prem deployments.

VCO is a cloud-based centralized management platform that helps admins configure, monitor, and manage VeloCloud SD-WANs (Software-Defined Wide Area Networks) and associated edge devices.

Tracked as CVE-2026-93952, this maximum-severity flaw stems from an improper input validation weakness and affects VCO deployments where certificate-based authentication from the VeloCloud Edge to VeloCloud Orchestrator (VCO) is configured.

Remote threat actors can exploit the vulnerability to access privileged internal VCO host functionality in low-complexity attacks that don't require privileges on the targeted system or user interaction.

"This issue was discovered externally and is known to be actively exploited," the company warned in a Tuesday advisory. "Access to the public portion of the VeloCloud Edge authentication certificate is required. A successful attack requires network access to the VCO web interface. VCO tenant or operator credentials are not required for this exposure."

Arista says that it has already patched hosted deployments running VCO 5.2.3.16 or later and VCO 6.4.2.8 or later and that it will also release security patches for VCO instances running 6.1.3.7 and below and 7.0.0.2 and below.

The U.S. Cybersecurity and Infrastructure Security Agency has also added CVE-2026-93952 to its Known Exploited Vulnerabilities catalog on Tuesday and ordered U.S. federal civilian executive branch agencies to secure their networks by Friday, September 25.

Indicators of compromise

While security patches are being deployed, admins should restrict access to the VCO web interface to administrative networks, review recent administrator activity for unusual changes, and monitor for connections from known malicious IP addresses.

Admins should review VCO web access logs for suspicious activity, such as requests containing encoded characters, unusual URL-like path components, references to local or internal services, or high request rates.

Arista also advised security teams to block the 142[.]93.149.77 and 104[.]248.126.159 IP addresses and review nginx logs for the x-vc-opt HTTP header, and said that unexpected outbound HTTP or HTTPS activity originating from the VCO host may also warrant further review.

"If compromise is suspected, operators should preserve VCO web access logs, backend application logs, system logs, database logs, and relevant file-system timestamps before remediation where operationally feasible," it added, and advised customers to contact the Arista Networks Technical Assistance Center (TAC) if they need additional assistance.

Since the start of the year, Arista patched two other zero-day flaws (CVE-2026-7473 in May and CVE-2026-16812 in July) that were being actively exploited in attacks and affected Extensible Operating System (EOS) and on-premises VeloCloud Orchestrator deployments, respectively.

Arista Networks is a Fortune 500 company and one of the largest United States corporations by revenue, with more than 10,000 customers worldwide.

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