---
id: "CVE-2026-120982"
page: "https://infrastack.ai/live/CVE-2026-120982"
kind: "vulnerability"
aliases: ["CVE-2026-120982"]
title: "Arista EOS: crafted BGP messages force repeated session resets, disrupting routing"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "Arista EOS", "fixed": ["4.37.0F", "4.36.3M", "4.35.7M", "4.34.9M", "4.33.11M"], "affected": "<= 4.36.2F (4.36.x), <= 4.35.6M (4.35.x), <= 4.34.8M (4.34.x), <= 4.33.10M (4.33.x), all End of Support trains", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["arista-eos", "bgp", "infrastructure", "network-operators"]
not_affected_if: ["no-bgp-configured", "peering-restricted-to-trusted-peers", "routing-model-ribd"]
published_at: "2026-11-10T20:18:53+00:00"
first_seen_at: "2026-11-10T20:46:03+00:00"
updated_at: "2026-11-10T20:58:28+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-120982", "first_seen_at": "2026-11-10T20:46:03+00:00"}, {"source": "analyst", "url": "https://www.arista.com/en/support/advisories-notices/security-advisory/25029-security-advisory-0207", "first_seen_at": "2026-11-10T20:58:28+00:00", "cites": ["https://www.arista.com/en/support/advisories-notices/security-advisory/25029-security-advisory-0207"]}]
exploit_sources: []
---

# Arista EOS: crafted BGP messages force repeated session resets, disrupting routing

Link for people: https://infrastack.ai/live/CVE-2026-120982 (this .md is for agents)

On Arista EOS devices with BGP configured, an unauthenticated attacker who can establish a BGP peering session can send crafted BGP messages. These cause repeated BGP session resets, which disrupts routing and traffic forwarding.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Arista EOS affected <= 4.36.2F (4.36.x), <= 4.35.6M (4.35.x), <= 4.34.8M (4.34.x), <= 4.33.10M (4.33.x), all End of Support trains fixed 4.37.0F, 4.36.3M, 4.35.7M, 4.34.9M, 4.33.11M

## How to check

Exposed only if BGP is configured AND the multi-agent routing model is in use. Run 'show ip bgp summary' ("% BGP is not active" means not exposed) and 'show running-config all | inc service routing protocols' ("model ribd" means not exposed; "model multi-agent" plus BGP means exposed if the version is affected). Then 'show version' and compare to affected: 4.36.2F and below, 4.35.6M and below, 4.34.8M and below, 4.33.10M and below, and all End of Support trains. Look for log signs: show logging | grep "NOTIFICATION.*UPDATE Message Error".

## Fix

Upgrade EOS to 4.37.0F, 4.36.3M, 4.35.7M, 4.34.9M or 4.33.11M or later in your train. No hotfix. Workaround: under router bgp, 'neighbor default received attribute discard 22' (re-enabling attribute 22 on any peer restores exposure); or use TCP-AO peer authentication.

## Timeline

- 2026-11-10T20:46:03+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-120982
- 2026-11-10T20:58:28+00:00 analyst https://www.arista.com/en/support/advisories-notices/security-advisory/25029-security-advisory-0207 — Read Arista SA 0207 (primary): affected/fixed versions, multi-agent condition, workaround all from the vendor page. Not exploited per Arista; no PoC checked; social not searched (published today).

## Documents

- [advisory] Arista Security Advisory 0207 (CVE-2026-120982) https://www.arista.com/en/support/advisories-notices/security-advisory/25029-security-advisory-0207

## From the sources

On affected platforms running Arista EOS with Border Gateway Protocol (BGP) configured, An unauthenticated attacker who can establish a BGP peering session with an affected device and can send specially crafted BGP messages to cause repeated BGP session resets, enabling sustained disruption to network routing and traffic forwarding.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_