Security Advisory 0211 .CSAF PDF

Date: November 10, 2026

 

Revision Date Changes
1.0 November 10, 2026 Initial release

The CVE-ID tracking this issue: CVE-2026-120978
CVSSv3.1 Base Score: 6.5 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
CVSSv4.0 Base Score: 6.0 (CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N)
Common Weakness Enumeration:  CWE-476  NULL Pointer Dereference, CWE-617 Reachable Assertion This vulnerability is being tracked by BUG 1924022

Description

On affected Arista EOS platforms running Border Gateway Protocol with Link State ( BGP-LS) and configured with the Dynamic Path Selection (DPS) consumer role, an attacker who has established an authenticated BGP-LS session with the device can send a crafted message to cause the BGP agent to restart unexpectedly. An Arista Pathfinder deployment is not required.

These issues were discovered internally by Arista, and the company is not aware of any malicious exploitation of these vulnerabilities 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

  • 4.36.2F and below releases in the 4.36.x train.
  • 4.35.6M and below releases in the 4.35.x train.
  • 4.34.8M and below releases in the 4.34.x train.
  • 4.33.10M and below releases in the 4.33.x train.
  • All releases in the 4.32.x train
  • All releases in the End of Support software release trains

Affected Platforms

The following products are affected by this vulnerability:
 

 

  • 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/XE7 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
    • ZTX-7200 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 cloud service delivery
  • CloudVision Portal, virtual appliance or physical appliance (including the CV-CUE on premises software)
  • CloudVision Appliance Software
  • CloudVision as-a-Service
  • CloudVision AGNI - Cloud service delivery
  • CloudVision AGNI - Virtual or physical appliance
  • 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

In order to be vulnerable to CVE-2026-120978, The following two conditions must be met:
At least one BGP-LS peer session is established, and Role(s) includes Consumer (DPS).

  1. BGP-LS configured
    switch(config)#show bgp link-state summary
BGP summary information for VRF default
Router identifier 0.0.0.1, local AS number 300
Neighbor Status Codes: m - Under maintenance
  Neighbor V AS           MsgRcvd   MsgSent  InQ OutQ  Up/Down State   NlriRcd NlriAcc NlriAdv
  12.0.0.3 4 300               82        83    0    0 01:02:33 Estab   0      0      1
switch(config)#
     
  2. DPS consumer is enabled:
    switch#show bgp instance | section Address family Link State:
Address family Link State:
  Role(s): Consumer (DPS)

    If BGP-LS is not configured or no peers are established, the device is not vulnerable. 

    The configuration is not affected if at least one of the following outputs matches:

    1. link-state is not configured.
     
    switch(config-router-bgp)#show bgp link-state summary
BGP summary information for VRF default
Router identifier 0.0.0.1, local AS number 300
Neighbor Status Codes: m - Under maintenance
  Neighbor V AS           MsgRcvd   MsgSent  InQ OutQ  Up/Down State   NlriRcd NlriAcc NlriAdv
     
    1. No BGP-LS or BGP-LS DPS consumer role is configured
     
    switch#show bgp instance | section Address family Link State:
Address family Link State:
  Role(s):
switch#

 

Indicators of Compromise

Unexpected BGP process restarts may indicate exploitation. Relevant messages may appear in the output of show logging:

switch#show logging | include PROCESS_TERMINATED.*Bgp
...
%PROCMGR-6-PROCESS_TERMINATED: 'Bgp' (PID=XXXX, status=-11) has terminated.
%PROCMGR-6-PROCESS_TERMINATED: 'Bgp' (PID=XXXX, status=-6) has terminated.
%SYS-4-RESTART_SERVICE: Service Bgp is not running. Attempting to restart it.

 

Mitigation

There are no configuration-level mitigations that fully resolve this issue without upgrading software.

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-2026-120978 has been fixed in the following releases:
  • 4.37.0F and later releases in the 4.37.x train
  • 4.36.3M and later releases in the 4.36.x train
  • 4.35.7M and later releases in the 4.35.x train
  • 4.34.9M and later releases in the 4.34.x train
  • 4.33.11M and later releases in the 4.33.x train

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
  • By email: This email address is being protected from spambots. You need JavaScript enabled to view it.
  • By telephone: List of regional telephone numbers

Receive notification for new advisories and notices:

Subscribe to the RSS feed and email notifications to receive periodic updates on new software releases, advisories, end of sale and field notices.