# CVE-2026-73444: Auth bypass in EOS

> An attacker on the local network can bypass VRRP authentication to become the master router, allowing them to intercept or modify traffic.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Sep 2026
- **Updated:** 16 Sep 2026
- **Also known as:** GHSA-c355-4cc9-9547

## What is CVE-2026-73444?

CVE-2026-73444 is a medium-severity authentication bypass vulnerability in Arista Networks EOS, published on 15 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

On affected platforms running Arista EOS with VRRPv2 IP Authentication Header (IP-AH) authentication configured, an unauthenticated attacker with access to the layer 2 network segment on which VRRP is running could bypass VRRP authentication and claim the virtual router master role, enabling the attacker to intercept, modify, or discard traffic that hosts on the segment send to the virtual gateway address.

Weakness: CWE-303 (Incorrect Implementation of Authentication Algorithm)

## Which versions are affected by CVE-2026-73444?


## How do I fix CVE-2026-73444?

No fix has been published for CVE-2026-73444 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-73444 being exploited?

There is no known exploitation of CVE-2026-73444 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-73444 and fix it if it is affected.

What it is: CVE-2026-73444 is a medium-severity authentication bypass vulnerability in Arista Networks EOS, published on 15 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-73444 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-2026-73444/ (Markdown: https://insights.sbomify.com/CVE-2026-73444/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-73444
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-73444
- OSV: https://osv.dev/vulnerability/CVE-2026-73444

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-73444/
Summaries are generated and may contain mistakes; the official description above is the record.