CVE-2025-5089 Overview
CVE-2025-5089 affects Arista EOS switches operating within a CloudVision eXchange (CVX) cluster. The vulnerability stems from improper input validation [CWE-20] in the handling of messages exchanged between an EOS switch and its connected CVX server. Malformed TCP packets sent between these endpoints can trigger a Sysdb agent crash on the EOS device, resulting in a soft reset of the switch. The same malformed traffic can crash agents on the CVX server, destabilizing the entire CVX cluster. Exploitation requires the attacker to already hold high-privilege access on one of the connected devices. EOS switches that are not connected to a CVX server are not affected.
Critical Impact
A privileged attacker on a CVX-connected device can send crafted TCP packets to crash the Sysdb agent on EOS switches or destabilize the CVX cluster, producing a denial-of-service condition.
Affected Products
- Arista EOS switches connected to a CVX server within a CVX cluster
- Arista CloudVision eXchange (CVX) server
- CVX cluster deployments processing inter-node management traffic
Discovery Timeline
- 2026-06-05 - CVE-2025-5089 published to NVD
- 2026-06-05 - Last updated in NVD database
Technical Details for CVE-2025-5089
Vulnerability Analysis
The vulnerability resides in the message-parsing logic governing communication between EOS switches and the CVX server. Neither endpoint enforces strict validation on the structure of messages it receives from its peer. When either side processes a malformed message, the parser fails in a way that crashes the responsible agent process. On the EOS side, the Sysdb agent crash triggers a soft reset of the switch, interrupting forwarding and management plane operations. On the CVX server, agent crashes destabilize the cluster, affecting fabric-wide state distribution.
Root Cause
The root cause is improper input validation [CWE-20] in the CVX-to-EOS and EOS-to-CVX message handling code paths. The parser does not verify message structure or field boundaries before dispatching the payload to internal handlers, allowing crafted input to push the agent into an unrecoverable state.
Attack Vector
Exploitation requires network access to the CVX management channel and high-privilege credentials on a connected device. The attacker uses that access to send custom TCP packets impersonating valid CVX or EOS messages. Because the attack originates from an authenticated peer in the cluster, traffic flows through trusted channels and bypasses perimeter controls. EOS switches not enrolled in a CVX cluster are not exposed to this attack path.
No proof-of-concept code is publicly available. See the Arista Security Advisory #0126 for protocol-level technical details.
Detection Methods for CVE-2025-5089
Indicators of Compromise
- Unexpected Sysdb agent crashes or soft resets on EOS switches enrolled in a CVX cluster
- Repeated agent restarts or process terminations on the CVX server affecting cluster stability
- Unscheduled failover events or loss of state synchronization between CVX peers
- Anomalous TCP traffic on the CVX management channel originating from a single authenticated peer
Detection Strategies
- Monitor EOS event logs for Sysdb agent termination messages and soft-reset events correlated with CVX session activity
- Track CVX server agent health and restart counters; alert on repeated crashes within short time windows
- Inspect CVX session logs for malformed message parsing errors and unexpected disconnect-reconnect cycles
Monitoring Recommendations
- Forward EOS syslog, agent crash dumps, and CVX cluster health metrics to a centralized SIEM for correlation
- Baseline normal CVX peer message volume and alert on deviations from authenticated peers
- Audit privileged account usage on all CVX-connected devices, since exploitation requires high-privilege access
How to Mitigate CVE-2025-5089
Immediate Actions Required
- Review the Arista Security Advisory #0126 and apply the fixed EOS and CVX releases identified by Arista
- Restrict and audit high-privilege accounts on EOS switches and CVX servers, since exploitation requires existing privileged access
- Segment the CVX management network from general administrative networks to limit reachable attack surface
Patch Information
Arista has published remediation guidance in Arista Security Advisory #0126. Operators should consult the advisory for the list of fixed EOS and CVX versions and upgrade affected nodes following Arista's recommended cluster upgrade procedure.
Workarounds
- Disable the CVX feature on switches that do not require cluster participation, since switches not connected to CVX are not affected
- Enforce strict access controls and multi-factor authentication on administrative accounts that can reach the CVX management channel
- Apply network ACLs to permit CVX traffic only from known cluster members and management hosts
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
