CVE-2026-73450 Security Advisory 0161
An unauthenticated attacker can cause traffic interruption by sending crafted packets to interfere with MLAG dual-primary detection on Arista EOS devices.
- 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-2026-73450?
CVE-2026-73450 is a high-severity denial of service vulnerability in Arista Networks EOS, published on 16 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 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.
Weakness: CWE-345
Which versions are affected by CVE-2026-73450?
How do I fix CVE-2026-73450?
No fix has been published for CVE-2026-73450 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-73450 being exploited?
There is no known exploitation of CVE-2026-73450 in the wild and no public exploit code.
Sources
Also known as GHSA-w26w-6gr3-j89v.