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Security Advisory 0216

6.0MediumCNA
Exploited
No known exploitation
Fix
Fixed in 4.32.0F, 4.33.0F
Who is exposed
Not reported

Do first: Upgrade to a fixed version: 4.32.0F, 4.33.0F.

Published
Last modified
Reference
Last checked
6/100 · provisional
None on Exploit-DB, Metasploit or GitHub

Summary

On affected platforms running Arista EOS with IEEE 802.1X authentication and MACsec using dynamically derived keys, sensitive authentication information may be recorded in diagnostic data during a Smart Switch Upgrade (SSU).

An attacker with administrative access on the device who obtains the affected diagnostic data could recover sensitive authentication information. This could potentially compromise the confidentiality and integrity of traffic protected by MACsec on the affected link.

The vulnerability is only exposed during and after an SSU reload where an active 802.1X session used for MACsec is present.

cve.now Index

6Pcve.now Index 6 of 100 · methodology v3 · provisional
  • Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
  • Exposure?/25Unknown. No advisory context yet
  • Reach?/20Unknown. No tracked technology or package matched
  • Severity6/10CVSS 6.0
  • No patch0/5No signal

What would change the score

  • Would score about 61 if added to CISA KEV
  • Would score about 56 if CISA's SSVC rates exploitation active
  • Would score about 28 if advisories confirm default setups are exposed

What to do

  • Upgrade to a fixed version: 4.32.0F, 4.33.0F.

Check your systems with an agent

Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.

Check whether my systems are affected by CVE-2026-120976 (Security Advisory 0216), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-120976 (entry last updated 2026-11-10):
Affected:
- Arista Networks EOS: from 4.22.0F, fixed in 4.32.0F; from 4.32.0F, fixed in 4.33.0F; from 4.33.0F, through 4.33.9M; from 4.34.0F, through 4.34.8M; from 4.35.0F, through 4.35.6M; from 4.36.0F, through 4.36.2F
Fixed versions: 4.32.0F, 4.33.0F.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-120976 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-120976 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://www.arista.com/en/support/advisories-notices/security-advisory/25038-security-advisory-0216
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-120976
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-120976.

Timeline

  1. CVE published
  2. First seen by cve.now

Affected versions

  • Arista Networks EOS

    From 4.22.0F · fixed in 4.32.0F; From 4.32.0F · fixed in 4.33.0F; From 4.33.0F · through 4.33.9M; From 4.34.0F · through 4.34.8M; From 4.35.0F · through 4.35.6M; From 4.36.0F · through 4.36.2F

Evidence 3

Vendor advisory · 1

Establishes: Affected and fixed versions.

  1. Advisory

CVE record · 2

Establishes: The identifier and description.

  1. Record
  2. Record

Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about CVE-2026-120976

Is CVE-2026-120976 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data

Which versions are affected by CVE-2026-120976?

EOS: from 4.22.0F before 4.32.0F; from 4.32.0F before 4.33.0F; from 4.33.0F through 4.33.9M; from 4.34.0F through 4.34.8M; from 4.35.0F through 4.35.6M; from 4.36.0F through 4.36.2F.Source: cve.now feed data

How do I fix CVE-2026-120976?

Upgrade to a fixed version: 4.32.0F, 4.33.0F.Source: cve.now feed data