CVE-2026-2379 Arista EOS IPsec Tunnel Sequence Number Mismatch via Interface Flaps when Anti-Replay is Disabled
Interface flaps can cause IPsec sequence number mismatches leading to unstable communication and potential denial of service on Arista EOS devices.
- 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-2026-2379?
CVE-2026-2379 is a high-severity denial of service vulnerability in Arista Networks EOS, published on 5 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
On affected platforms with hardware IPSec support running Arista EOS with certain IPsec features enabled, EOS may exhibit unexpected behavior in specific cases. Physical interface flaps and certain agent restarts can cause IPsec tunnel re-establishment with existing Security Associations, resulting in sequence number mismatches between tunnel endpoints potentially causing unstable communication.
Weakness: CWE-672
Which versions are affected by CVE-2026-2379?
How do I fix CVE-2026-2379?
No fix has been published for CVE-2026-2379 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-2026-2379 being exploited?
There is no known exploitation of CVE-2026-2379 in the wild and no public exploit code.
Sources
Also known as GHSA-qm38-553v-42w8.