Security Advisory 0159 PDF

Date: September 9, 2026

Revision Date Changes
1.0 September 9, 2026 Initial release

The CVE-ID tracking this issue: CVE-2026-73462
CVSSv3.1 Base Score: 6.5 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVSSv4.0 Base Score: 7.1 (CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N)
Common Weakness Enumeration: CWE-125 - Out-of-bounds read
This vulnerability is being tracked by BUG1570495, BUG1571339

Description

On affected platforms running Arista EOS with IGMP (Internet Group Management Protocol) snooping configured (enabled by default on all VLANs), a network-adjacent unauthenticated attacker can send malformed network packets on an affected VLAN to cause the IGMP snooping agent to terminate unexpectedly. This results in a temporary disruption of multicast traffic management, which may cause multicast traffic to be flooded to all ports of the affected VLAN until the service recovers. Repeated exploitation could result in a prolonged loss of intended multicast forwarding behavior.

This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

 

Vulnerability Assessment

Platform and Software Applicability Note

To determine actual exposure, operators should first check their software versions against the "Affected Software" list below. If your software release is not listed, your deployment is not vulnerable, regardless of the hardware platform in use.

 

Affected Software

EOS Versions
  • 4.36.1F and earlier versions in the 4.36.x train
  • 4.35.5M and earlier versions in the 4.35.x train
  • 4.34.7.1M and earlier versions in the 4.34.x train
  • 4.33.8M and earlier versions in the 4.33.x train
  • All prior releases

Affected Platforms

The following products are affected by this vulnerability:

 

 
  • All Arista EOS-based products:
    • 710 Series
    • 720D Series
    • 720XP/722XPM Series
    • 750X Series
    • 7010TX Series 
    • 7020R/R4 Series
    • 7130 Series running EOS
    • 7170 Series
    • 7050X3/X4 Series
    • 7060X/X2/X4/X5/X6 Series
    • 7260X/X3 Series
    • 7280R/R2/R3/R4 Series
    • 7300X/X3 Series
    • 7320X Series
    • 7358X4 Series
    • 7368X4 Series
    • 7388X5 Series
    • 7500R/R2/R3 Series
    • 7800R3/R4 Series
    • 7700R4 Series
    • AWE 5000 Series
    • AWE 7200R Series
    • CloudEOS
    • cEOS-lab
    • vEOS-lab
    • CloudVision eXchange, virtual or physical appliance
 
The following product versions and platforms are not affected by this vulnerability:
 

 

  • WI-FI Access Points
  • CloudVision CUE, virtual appliance or physical appliance
  • CloudVision CUE cloud service delivery
  • CloudVision Portal, virtual appliance or physical appliance
  • CloudVision Appliance Software
  • CloudVision as-a-Service
  • CloudVision AGNI - Cloud service delivery
  • CloudVision AGNI - Virtual or physical appliance
  • Arista 7130 Systems running MOS
  • Arista Converged Cloud Fabric (formerly Big Switch BCF)
  • DANZ Monitoring Fabric (DMF) - Controller Appliance
  • DANZ Monitoring Fabric (DMF) - Analytics Node Appliance
  • DANZ Monitoring Fabric (DMF) - Recorder Node Appliance
  • DANZ Monitoring Fabric (DMF) - Service Node Appliance
  • Arista Multi Cloud Director (formerly Big Switch MCD)
  • Arista Network Detection and Response (NDR) Security Platform (Formerly Awake NDR)
  • Arista Edge Threat Management - Arista NG Firewall and Arista Micro Edge (Formerly Untangle)
  • Arista NetVisor OS, Arista NetVisor UNUM, and Insight Analytics (Formerly Pluribus)
  • VeloCloud Orchestrator (Formerly VeloCloud Orchestrator by Broadcom)
  • VeloCloud Gateway (Formerly VeloCloud Gateway by Broadcom)
  • VeloCloud Edge (Formerly VeloCloud Edge by Broadcom)

Required Configuration for Exploitation

IGMP snooping agent is instantiated by default on EOS. No configuration is required.

Indicators of Compromise

While no reliable Indicators of Compromise exist, persistent crashing of the IGMP snooping agent may indicate exploitation of the issue. The below logging messages show IgmpSnooping being terminated. Unexpected and persistent terminations are an indicator of compromise:

 

router#show logging | grep IgmpSnooping
%PROCMGR-6-PROCESS_TERMINATED: 'IgmpSnooping' (PID=<pid>) has terminated with signal 11 (core dumped).

Mitigation

There is no mitigation or workaround available. Disabling IGMP snooping will NOT mitigate the issue

Resolution

The recommended resolution is to upgrade to a remediated software version at your earliest convenience. Arista recommends customers move to the latest version of each release that contains all the fixes listed below. For more information about upgrading see EOS User Manual: Upgrades and Downgrades

CVE-2026-73462 has been fixed in the following releases:
 
  • 4.36.2F and later releases in the 4.36.x train
  • 4.35.6M and later releases in the 4.35.x train
  • 4.34.8M and later releases in the 4.34.x train
  • 4.33.9M and later releases in the 4.33.x train

Hotfix

No hotfixes exist for this issue

For More Information

If you require further assistance, or if you have any further questions regarding this security notice, please contact the Arista Networks Technical Assistance Center (TAC) by one of the following methods:

Open a Service Request

Contact information needed to open a new service request may be found at:
https://www.arista.com/en/support/customer-support