Low severity · published Sep 14, 2026
CVE-2026-77191
All of the CVEs covered in this advisory apply to affected platforms running Arista EOS with 802.1X authentication and authorization enabled and Access Control Lists (ACLs) configured for per-supplicant policy enforcement. An authenticated supplicant on an
2.6
CVSS
0.2%
EPSS
No
On KEV
Description
An authenticated supplicant on an adjacent network may bypass intended network authorization policy and send unrestricted traffic during a brief window (milliseconds to seconds) between the completion of the authentication phase and the full enforcement of its assigned ACL.
CVSS vector
CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Adjacent
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 13% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EO
EOS · Arista Networks
4.35.0 through 4.35.0.3F; 4.34.0 through 4.34.5M; 0.0.0 through 4.33.7.1M · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-77191
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-77191
www.arista.com
https://www.arista.com/en/support/advisories-notices/security-advisory/24706-security-advisory-0150
More from EOS
5.8
CVE-2026-7473
Arista EOS Unexpected Tunnel Protocol Decapsulation and Forwarding Bypass
10.0
CVE-2026-73456
Under certain circumstances, an unauthenticated gNPSI client can craft a malicious request to allow arbitrary code execution, granting an attacker full administrative control over the compromised switch.
10.0
CVE-2026-73453
An unauthenticated P4Runtime (Programming Protocol-Independent Packet Processors Runtime) client can achieve arbitrary code execution under certain conditions on affected platforms running Arista EOS
9.6
CVE-2026-73437
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/destinat
9.6
CVE-2024-27892
On affected platforms running Arista EOS with OpenConfig configured, a gNMI Set request can be run when it should have been rejected (SSL Profiles Enabled).