Vulnerability · Published Sep 15, 2026 · Assigned by Arista
CVE-2026-73437On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay configured, an unauthenticated attacker with network access could send a crafted DHCP reply packet from an IP address that is not configured as a helper/destinat
Critical 9.6
In plain English
A critical-severity insufficient verification of data authenticity in EOS from Arista Networks. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities).
Official description
On affected platforms running Arista EOS with Dynamic Host Configuration Protocol (DHCP) relay configured, an unauthenticated attacker with network access could send a crafted DHCP reply packet from an IP address that is not configured as a helper address, and the relay agent would forward it to clients without validating the source. This could allow the attacker to supply clients with malicious network configuration parameters, potentially resulting in traffic interception or denial of service for affected clients.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Arista Networks | EOS | 4.36.0 – through 4.36.1F4.35.0 – through 4.35.5M4.34.0 – through 4.34.7.1M4.33.0 – through 4.33.9M |
Weakness: CWE-345 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H