---
schema: 1
kind: vulnerability
title: "CVE-2026-16812 — Arista VeloCloud Orchestrator on-prem: unauthenticated OS command injection on an interface exposed by default, confirmed exploited (CVSS 10.0)"
headline: "Arista patches an actively exploited unauthenticated command-injection flaw in on-prem VeloCloud Orchestrator"
summary: >
  Arista disclosed CVE-2026-16812 on 2026-07-27, an unauthenticated OS command-injection flaw (CVSS 10.0,
  CWE-78) in on-prem VeloCloud Orchestrator, the management plane for a VeloCloud SD-WAN fleet, and states
  it is already being exploited in the wild; CISA added it to the Known Exploited Vulnerabilities catalog
  the same day. The orchestrator web interface is exposed by default, no configuration can prevent the
  exposure, and no tenant or operator credentials are required. Fixed builds are 5.2.3.14, 6.1.3.4 and
  6.4.2.4 on their respective trains; because a compromised orchestrator may reach the Edge devices it
  manages, Arista's post-remediation steps call for credential rotation and validation of managed device
  state, not just an upgrade.
discovered_at: "2026-07-28T04:45:00Z"
event_date: "2026-07-27"
run_id: 2026-07-28T0409Z-intel
priority: critical
immediate_action:
  title: "Patch or network-isolate every on-prem VeloCloud Orchestrator today"
  action: >
    Arista states this unauthenticated command-injection flaw in on-prem VeloCloud Orchestrator is already
    being exploited in the wild, and that the vulnerable interface is exposed by default with no
    configuration that can turn the exposure off. Upgrade to 5.2.3.14, 6.1.3.4 or 6.4.2.4 on the matching
    release train immediately; where the train in use has no fixed build, restrict the orchestrator web
    interface to trusted administrative networks, which is the only exposure-reducing control Arista
    offers — its other three mitigations are monitoring measures, not preventive ones. Treat any
    orchestrator that was network-reachable before patching as a compromise-assessment target — Arista
    warns that compromise of the orchestrator may extend to the VeloCloud Edge devices it manages, so
    rotate credentials, certificates and key material and validate managed-device state.
tags: [vulnerabilities, actively-exploited, rce, pre-auth, cisa-kev, patch-available, default-config]
regions: [global]
sectors: [technology, telco]
entities: []
techniques: [T1190, T1059, T1072]
affected_products: ["Arista VeloCloud Orchestrator On-Prem"]
cves:
  - id: CVE-2026-16812
    cvss: "10.0"
    epss: null
    type: rce
    vector: zero-click
    auth: pre-auth
    status: [exploited, cisa-kev, patch-available]
    affected: "On-prem VCO 5.2.x before 5.2.3.14, 6.1.x before 6.1.3.4, 6.4.x before 6.4.2.4, and 7.0.x before 7.0.0.1; Arista notes end-of-support versions were not assessed. VCO Hosted and Dedicated were patched before the advisory published, and VeloCloud Gateway, VeloCloud Edge and Arista EOS-based products are not affected."
    fixed: "5.2.3.14 and later in the 5.2 train, 6.1.3.4 and later in the 6.1 train, 6.4.2.4 and later in the 6.4 train — the three builds Arista's Resolution section enumerates. The advisory's affected-software list implies 7.0.0.1 for the 7.0 train, but the Resolution section names no 7.0 build; operators on 7.0.x should confirm the fixed release with Arista TAC."
sources:
  - url: "https://www.arista.com/en/support/advisories-notices/security-advisory/24364-security-advisory-0144"
    publisher: "Arista Networks (Security Advisory 0144)"
    date: "2026-07-27"
    role: primary
  - url: "https://www.cisa.gov/news-events/alerts/2026/07/27/cisa-adds-two-known-exploited-vulnerabilities-catalog"
    publisher: "CISA"
    date: "2026-07-27"
    role: corroborating
closed_sources: []
evidence:
  - quote: "This issue was discovered externally and is known to be actively exploited."
    publisher: "Arista Networks (Security Advisory 0144)"
  - quote: "VCO is exposed by default. There is no configuration that can prevent the exposure. A successful attack requires network access to the VCO web interface. VCO tenant or operator credentials are not required for this exposure."
    publisher: "Arista Networks (Security Advisory 0144)"
  - quote: "Compromises to the VCO platform may allow attackers access to the VeloCloud Edge devices as well."
    publisher: "Arista Networks (Security Advisory 0144)"
verification: multi-source
sourcing_note: "Arista is the CNA for this CVE and is the primary disclosing party for its own product (reliability A); both CVSS strings quoted here are Arista's own, and the identifier and scoring were additionally verified against the NVD record during this run. Its exploitation statement is corroborated independently by CISA's addition of the CVE to the Known Exploited Vulnerabilities catalog on the same day, which is why credibility is 1. Arista publishes attacker source addresses in its own advisory; those are deliberately not reproduced here — operators should take them from the vendor page directly. Arista's advisory describes the flaw only as reachable 'privileged internal functionality' and does not name the vulnerable component or endpoint, so no component-level detail is asserted below."
confidence: high
update_of: null
references: []
deep_dive: false
deep_dive_category: null
org_triage: null
classification:
  reliability: A
  credibility: 1
watchlist_hit: false
actions:
  - "Upgrade every on-prem VeloCloud Orchestrator to 5.2.3.14, 6.1.3.4 or 6.4.2.4 on its matching release train; where the train in use has no fixed build listed, restrict the orchestrator web interface to trusted administrative networks and open a TAC case, because no configuration disables the exposed functionality."
  - "For any on-prem VCO that was network-reachable before it was patched, complete Arista's post-remediation steps rather than stopping at the upgrade — rotate orchestrator credentials, certificates and key material, and validate the configuration state of the VeloCloud Edge devices that orchestrator manages."
migrated_from: null
---

Arista disclosed CVE-2026-16812 on 2026-07-27: an improper-neutralisation flaw (CWE-78, OS command injection) in on-prem VeloCloud Orchestrator (VCO) that lets a remote attacker reach "privileged internal functionality" and act on the orchestrator host, scored 10.0 on both CVSS 3.1 and CVSS 4.0 ([Arista, 2026-07-27](https://www.arista.com/en/support/advisories-notices/security-advisory/24364-security-advisory-0144)). Two properties make this worse than the score alone suggests. First, there is no exploitation precondition to remove: Arista states the interface "is exposed by default", that "[t]here is no configuration that can prevent the exposure", and that tenant or operator credentials are not required — the only reachability control is network placement ([Arista, 2026-07-27](https://www.arista.com/en/support/advisories-notices/security-advisory/24364-security-advisory-0144)). Second, VCO is a management plane, not an edge device: Arista's own post-remediation guidance warns that "[c]ompromises to the VCO platform may allow attackers access to the VeloCloud Edge devices as well", so the blast radius is the managed SD-WAN fleet rather than one appliance ([Arista, 2026-07-27](https://www.arista.com/en/support/advisories-notices/security-advisory/24364-security-advisory-0144)).

Exploitation is not a projection. Arista states the issue "was discovered externally and is known to be actively exploited", and CISA added CVE-2026-16812 to the Known Exploited Vulnerabilities catalog on the day of disclosure ([CISA, 2026-07-27](https://www.cisa.gov/news-events/alerts/2026/07/27/cisa-adds-two-known-exploited-vulnerabilities-catalog)). Affected are on-prem VCO 5.2.x before 5.2.3.14, 6.1.x before 6.1.3.4, 6.4.x before 6.4.2.4 and 7.0.x before 7.0.0.1; Arista's Resolution section enumerates fixed builds for the 5.2, 6.1 and 6.4 trains only, so 7.0.x operators should confirm their target release with the vendor rather than assume one. Hosted and Dedicated orchestrators were patched ahead of the advisory, and VeloCloud Gateway, VeloCloud Edge and the Arista EOS-based product lines are not in scope ([Arista, 2026-07-27](https://www.arista.com/en/support/advisories-notices/security-advisory/24364-security-advisory-0144)).

Detection, telemetry class first: the orchestrator's own web-access and reverse-proxy logs are the primary surface — Arista directs operators to requests carrying unusual URL-like path components, encoded characters or references to local or internal services, and to elevated request rates against the management interface. Pair that with backend application and system logs around the same timestamps for command execution, file creation, database export or archive artifacts that no administrator session accounts for, and with egress telemetry for outbound HTTP/HTTPS originating from the orchestrator host itself ([Arista, 2026-07-27](https://www.arista.com/en/support/advisories-notices/security-advisory/24364-security-advisory-0144)). The discriminator that carries the most weight here is directionality and provenance rather than payload shape: a management appliance legitimately receives administrative sessions and pushes configuration to its managed Edge devices, but it has little reason to originate arbitrary outbound web traffic, and configuration changes or privileged maintenance actions that correlate to no operator session are the anomaly Arista itself flags — the vendor states plainly that no single definitive indicator of compromise exists for this issue, so sequence and correlation carry the detection rather than any one artifact. Hardening is limited to what network placement can buy: Arista's interim control is restricting the web interface to trusted administrative networks, since the exposed functionality cannot be switched off in configuration.