---
id: "CVE-2026-121295"
page: "https://infrastack.ai/live/CVE-2026-121295"
kind: "vulnerability"
aliases: ["CVE-2026-121295"]
title: "Arista EOS: crafted S-BFD packet crashes kernel and reboots switch"
severity: "critical"
cvss: 9.2
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["arista-eos", "infrastructure", "network-gear", "s-bfd"]
not_affected_if: ["no-s-bfd-configured", "no-s-bfd-peering"]
published_at: "2026-11-10T20:18:55+00:00"
first_seen_at: "2026-11-10T20:46:04+00:00"
updated_at: "2026-11-10T20:50:15+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121295", "first_seen_at": "2026-11-10T20:46:04+00:00"}, {"source": "analyst", "url": "https://vuldb.com/cve/CVE-2026-121295", "first_seen_at": "2026-11-10T20:50:15+00:00", "cites": ["https://vuldb.com/cve/CVE-2026-121295", "https://nvd.nist.gov/vuln/detail/CVE-2026-121295"]}]
exploit_sources: []
---

# Arista EOS: crafted S-BFD packet crashes kernel and reboots switch

Link for people: https://infrastack.ai/live/CVE-2026-121295 (this .md is for agents)

Per the CVE text, on Arista EOS devices configured as S-BFD peers an unauthenticated attacker could send a crafted S-BFD PDU to an initiator device, crashing its kernel and rebooting it. Affected and fixed EOS versions are not yet confirmed from Arista's advisory.

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

## How to check

Unknown until Arista's advisory is read. Per the CVE text, only EOS devices configured as S-BFD peers (initiator side) are in scope: look for seamless BFD (S-BFD) in the running config; if absent you can likely skip it.

## Timeline

- 2026-11-10T20:46:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121295
- 2026-11-10T20:50:15+00:00 analyst https://vuldb.com/cve/CVE-2026-121295 — CVE published today (Nov 10 2026, Arista CNA, CVSS 8.6, CWE-400). Arista advisory not indexed yet and arista.com blocks fetch (Client Challenge), so affected/fixed EOS versions unknown; nothing verified. Revisit for the Arista advisory (BUG id, fixed trains) and S-BFD config check. Sep 2026 Arista advisories (e.g. 0154 BFD) are different CVEs.

## Documents

- [describes] VulDB: CVE-2026-121295 in EOS (MITRE/Arista CNA text) https://vuldb.com/cve/CVE-2026-121295
- [describes] NVD: CVE-2026-121295 https://nvd.nist.gov/vuln/detail/CVE-2026-121295

## From the sources

On affected platforms running Arista EOS configured as S-BFD peers, an unauthenticated attacker could send a crafted S-BFD PDU to an initiator device. This crafted PDU could cause the kernel on the initiator device to crash, resulting in an unexpected device reboot.

---

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