Arista EOS up to 4.36.2F 802.1X improper authorization

Summaryinfo

A vulnerability described as critical has been identified in Arista EOS up to 4.36.2F. This issue affects some unknown processing of the component 802.1X. Executing a manipulation can lead to improper authorization. The identification of this vulnerability is CVE-2026-120977. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Arista EOS up to 4.36.2F and classified as critical. This vulnerability affects an unknown code block of the component 802.1X. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

On affected platforms running Arista EOS with 802.1X with Dynamic Host Configuration Protocol (DHCP) device profiling enabled, a network-adjacent attacker can send a crafted DHCP packet to force the device to record a spoofed device profile. This may potentially allow the authenticated supplicant to acquire unauthorized access to a network segment with elevated privileges.

The advisory is available at arista.com. This vulnerability was named CVE-2026-120977 since 11/03/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1548.002 by the MITRE ATT&CK project.

Upgrading to version 4.32.0F or 4.33.0F eliminates this vulnerability.

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Productinfo

Vendor

• Arista

Name

• EOS

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13
• 4.14
• 4.15
• 4.16
• 4.17
• 4.18
• 4.19
• 4.20
• 4.21
• 4.22
• 4.23
• 4.24
• 4.25
• 4.26
• 4.27
• 4.28
• 4.29
• 4.30
• 4.31
• 4.32
• 4.33.9M
• 4.34.7M
• 4.35.5M
• 4.36.2F

License

• commercial

CPE 2.3info

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CPE 2.2info

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