CVE-2026-73437 Missing authorization in EOS
An unauthenticated attacker can send crafted DHCP replies to intercept traffic or cause denial of service on clients when DHCP relay is configured.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-73437?
CVE-2026-73437 is a medium-severity missing authorization 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 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.
Weakness: CWE-345
Which versions are affected by CVE-2026-73437?
How do I fix CVE-2026-73437?
No fix has been published for CVE-2026-73437 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-73437 being exploited?
There is no known exploitation of CVE-2026-73437 in the wild and no public exploit code.
Sources
Also known as GHSA-qg3p-gw27-mvmj.