CVE-2024-27891 Security feature bypass in EOS
Attackers can bypass egress ACLs on Arista EOS devices when MACsec is enabled, allowing unauthorized packet transmission.
- 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-2024-27891?
CVE-2024-27891 is a medium-severity vulnerability in Arista Networks EOS, published on 4 Jun 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 MACsec and egress ACLs configured on the same interfaces, the ACL policies may not be enforced for packets egressing on those ports. This can cause outgoing packets to incorrectly be allowed or denied.
Weakness: CWE-284
Which versions are affected by CVE-2024-27891?
How do I fix CVE-2024-27891?
No fix has been published for CVE-2024-27891 yet. Limit exposure of the affected software until one is available.
Is CVE-2024-27891 being exploited?
There is no known exploitation of CVE-2024-27891 in the wild and no public exploit code.
Sources
Also known as GHSA-6r39-6chc-xxhc.