How do I check whether I am affected by CVE-2026-120979?

Exposed only if all are true: (1) EOS version is 4.36.2F or lower in 4.36.x, 4.35.6M or lower in 4.35.x, 4.34.8M or lower in 4.34.x, 4.33.10M or lower in 4.33.x, any 4.32.x, or an End-of-Support train; (2) 'show bgp link-state summary' shows at least one BGP-LS peer in Estab state; (3) 'show adaptive-virtual-topology path | section Role:' prints 'Role: pathfinder'. If BGP-LS is not configured, no peer is established, or the role is edge, zone transit, region transit or unknown, the device is not affected. Signs of abuse: unexpected active-path changes or a high rate of SFE-6-PATH_ACTIVE / SFE-6-PATH_INACTIVE syslog messages ('show logging | include SFE-6-PATH_ACTIVE|SFE-6-PATH_INACTIVE'). Arista states there are no configuration-level mitigations that fully resolve this without upgrading.

What is the fix for CVE-2026-120979?

Upgrade EOS to 4.37.0F or later, 4.36.3M, 4.35.7M, 4.34.9M or 4.33.11M (or later in the same train). No hotfix. 4.32.x and End-of-Support trains have no listed fix, so move to a fixed train.

Post Share

HIGH8.1CVSS · psirt@arista.com

NO KNOWN
EXPLOIT

EOS · CVE-2026-120979 · Infrastructure

Arista Pathfinder: crafted BGP-LS packet disrupts WAN path selection

Q: Who is not affected by CVE-2026-120979?

Not affected if: fixed-eos-version, no-bgp-ls-dps, no-bgp-ls-peer, no-pathfinder, not-pathfinder-role.

FIX → 4.37.0F +4 ✓ verified

An attacker with an authenticated BGP-LS session to an Arista EOS device configured for Dynamic Path Selection can send a crafted BGP packet. This causes incorrect WAN path selection and disrupts traffic forwarding.

first public Nov 10, 2026 · 2 sources

Could this affect your app?

Free first check from your website. Connect your repo for the full answer.

01 · Who is affected

✓ Verified Nov 10

Arista says only AWE 5000 Series, AWE 7200R Series and CloudEOS are affected, and only when configured as a Pathfinder node with an established BGP-LS peer session. An attacker with an authenticated BGP-LS session can send a crafted BGP packet that causes incorrect WAN path selection and disrupts forwarding. Teams without Pathfinder/BGP-LS, and Arista's listed switch series, CloudVision, VeloCloud and Wi-Fi products, can skip it.

eos<= 4.36.2F, <= 4.35.6M, <= 4.34.8M, <= 4.33.10M, all 4.32.xfixed in 4.37.0F, 4.36.3M, 4.35.7M, 4.34.9M, 4.33.11M

Not affected if fixed-eos-version, no-bgp-ls-dps, no-bgp-ls-peer, no-pathfinder, not-pathfinder-role

Who cares arista, awe, bgp-ls, cloudeos, eos, network, pathfinder, wan

02 · How to check

✓ Verified Nov 10

Exposed only if all are true: (1) EOS version is 4.36.2F or lower in 4.36.x, 4.35.6M or lower in 4.35.x, 4.34.8M or lower in 4.34.x, 4.33.10M or lower in 4.33.x, any 4.32.x, or an End-of-Support train; (2) show bgp link-state summary shows at least one BGP-LS peer in Estab state; (3) show adaptive-virtual-topology path | section Role: prints

Exploited: No reports yet
Public exploit: None on GitHub
EPSS: Not scored
Last updated: Nov 10, 2026

How it unfolded

2 events · Nov 10, 2026 → Nov 10, 2026

Nov 10, 202620:46 UTCNVD CVE-2026-120979
Nov 10, 202621:00 UTCInfraStack Analyst Read Arista Security Advisory 0212 (vendor, Nov 10 2026): affected/fixed EOS versions, exact check commands, no mitigation, no hotfix. Not exploited per Arista; no PoC. Social search skipped (new advisory, no CVE-id posts expected).moreless

What the sources say, verbatim

440 characters

This vulnerability affects customers using Arista Pathfinder for WAN path selection with Border Gateway Protocol-Link State (BGP-LS) configured for Dynamic Path Selection (DPS). On affected platforms running Arista EOS with BGP-LS configured for DPS, an attacker who has established an authenticated BGP-LS session with the device can send a specially crafted BGP packet to cause incorrect WAN path selection and disrupt traffic forwarding.

Sources and references

NVD: CVE-2026-120979Nov 10, 2026
Arista Security Advisory 0212Advisory · arista.com

This page as .md · .json · CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.

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Post Share

HIGH8.1CVSS · psirt@arista.com

NO KNOWN
EXPLOIT

EOS · CVE-2026-120979 · Infrastructure

Arista Pathfinder: crafted BGP-LS packet disrupts WAN path selection

FIX → 4.37.0F +4 ✓ verified

first public Nov 10, 2026 · 2 sources

Could this affect your app?

Free first check from your website. Connect your repo for the full answer.

01 · Who is affected

✓ Verified Nov 10

eos<= 4.36.2F, <= 4.35.6M, <= 4.34.8M, <= 4.33.10M, all 4.32.xfixed in 4.37.0F, 4.36.3M, 4.35.7M, 4.34.9M, 4.33.11M

Not affected if fixed-eos-version, no-bgp-ls-dps, no-bgp-ls-peer, no-pathfinder, not-pathfinder-role

Who cares arista, awe, bgp-ls, cloudeos, eos, network, pathfinder, wan

02 · How to check

✓ Verified Nov 10

Exposed only if all are true: (1) EOS version is 4.36.2F or lower in 4.36.x, 4.35.6M or lower in 4.35.x, 4.34.8M or lower in 4.34.x, 4.33.10M or lower in 4.33.x, any 4.32.x, or an End-of-Support train; (2) show bgp link-state summary shows at least one BGP-LS peer in Estab state; (3) show adaptive-virtual-topology path | section Role: prints

Exploited: No reports yet
Public exploit: None on GitHub
EPSS: Not scored
Last updated: Nov 10, 2026

How it unfolded

2 events · Nov 10, 2026 → Nov 10, 2026

Nov 10, 202620:46 UTCNVD CVE-2026-120979
Nov 10, 202621:00 UTCInfraStack Analyst Read Arista Security Advisory 0212 (vendor, Nov 10 2026): affected/fixed EOS versions, exact check commands, no mitigation, no hotfix. Not exploited per Arista; no PoC. Social search skipped (new advisory, no CVE-id posts expected).moreless

What the sources say, verbatim

440 characters

Sources and references

NVD: CVE-2026-120979Nov 10, 2026
Arista Security Advisory 0212Advisory · arista.com

NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.

Check it with your coding agent

It reads this page and tells you if your code is affected.

Claude CodeCodexCursorAdd to your agent

Are you affected?

Ask from here. InfraStack checks the affected versions against your stack and answers in your inbox.

InfraStack checks the affected versions against your stack and answers in Slack, with the evidence and the fix.

Run the check

Get the next EOS threat the day it hits your stack.

Start free

Arista Pathfinder: crafted BGP-LS packet disrupts WAN path selection

01 · Who is affected

02 · How to check

How it unfolded

What the sources say, verbatim

Sources and references

Read next

Get the next EOS threat the day it hits your stack.

Arista Pathfinder: crafted BGP-LS packet disrupts WAN path selection

01 · Who is affected

02 · How to check

How it unfolded

What the sources say, verbatim

Sources and references

Read next

Get the next EOS threat the day it hits your stack.

03 · The fix