# CVE-2026-73451: Security feature bypass in EOS

> Restarting secondary switchcards on Arista EOS devices with specific ACL configurations can disable security filters, allowing unauthorized network traffic.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** GHSA-66c7-m7g9-9qrj

## What is CVE-2026-73451?

CVE-2026-73451 is a medium-severity vulnerability in Arista Networks EOS, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

On affected platforms running Arista EOS with dual switch cards and with ingress Security ACLs configured on Switched Virtual Interfaces (SVI) in shared mode, restarting of the secondary switchcard forwarding agent or insertion of secondary switchcard, can cause security ACLs on shared SVIs to stop functioning. This may result in incorrect packet permit/deny behavior.

This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

Weakness: CWE-1419 (Incorrect Initialization of Resource)

## Which versions are affected by CVE-2026-73451?


## How do I fix CVE-2026-73451?

No fix has been published for CVE-2026-73451 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-73451 being exploited?

There is no known exploitation of CVE-2026-73451 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-73451 and fix it if it is affected.

What it is: CVE-2026-73451 is a medium-severity vulnerability in Arista Networks EOS, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-73451 in the wild and no public exploit code.

Affected product: Arista Networks EOS. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-73451/ (Markdown: https://insights.sbomify.com/CVE-2026-73451/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-73451
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-73451
- OSV: https://osv.dev/vulnerability/CVE-2026-73451

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-73451/
Summaries are generated and may contain mistakes; the official description above is the record.