Description
On affected platforms running Arista EOS with MLAG Dual Primary Detection configured, an unauthenticated attacker with access to the Dual Primary Detection network segment can send specially crafted packets to interfere with the dual-primary state. If the MLAG primary switch fails while these packets are present, the secondary switch incorrectly concludes it is in a dual-primary condition and err-disables its interfaces, leading to a traffic interruption.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Arista Networks | EOS | 4.36.0 – ≤ 4.36.1F, 4.35.0 – ≤ 4.35.5M, 4.34.0 – ≤ 4.34.7.1M, 4.33.0 – ≤ 4.33.9M, 0.0.0 – < 4.33.0 | 4.33.0 |
Advisories 1
- WID-SEC-2026-3287 Arista EOS: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 16, 2026
References
- Security Advisory 0161 vendor-advisory