CVE-2026-73458 Denial of service in EOS
A crafted packet can disrupt authenticated BFD sessions on Arista EOS, causing network instability and routing changes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-73458?
CVE-2026-73458 is a critical denial of service vulnerability in Arista Networks EOS, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
On affected platforms running Arista EOS with authenticated Bidirectional Forwarding Detection (BFD) sessions configured, a specially crafted packet can cause the BFD session(s) to go down. This may result in undesirable network changes because various routing protocols monitor status on BFD session(s).
Weakness: CWE-303
Which versions are affected by CVE-2026-73458?
How do I fix CVE-2026-73458?
No fix has been published for CVE-2026-73458 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-2026-73458 being exploited?
There is no known exploitation of CVE-2026-73458 in the wild and no public exploit code.
Sources
Also known as GHSA-78f4-9r4h-vc9q.