CVE-2026-19641
Received Received - Intake

Authentication Session Exhaustion in Arista EOS

Publication date: 2026-09-15

Last updated on: 2026-09-15

Assigner: Arista Networks, Inc.

Description
On affected platforms running Arista EOS with password authentication configured, a specially crafted password can create orphan authentication sessions. Repeated exploitation of this issue can exhaust available authentication resources, resulting in legitimate users being unable to log in to the device. This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

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Meta Information

Published
2026-09-15
Last Modified
2026-09-15
Generated
2026-09-15
AI Q&A
2026-09-15
EPSS Evaluated
N/A
NVD
CVE-2026-19641
EUVD
EUVD-2026-79141

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
arista eos *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-116 The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.

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Executive Summary

This vulnerability in Arista EOS with password authentication allows a specially crafted password to create orphan authentication sessions. Repeated exploitation can exhaust authentication resources, preventing legitimate users from logging in.

Detection Guidance

Monitor authentication session counts on Arista EOS devices. Check for unusually high numbers of orphaned sessions using commands like 'show aaa sessions' or 'show authentication sessions'. Look for patterns of failed login attempts or sessions that persist without active users.

Impact Analysis

If exploited, this vulnerability could block access to Arista EOS devices for authorized users due to resource exhaustion. It may disrupt network management and operations.

Mitigation Strategies

Disable password authentication if possible and switch to more secure methods like SSH keys or TACACS+/RADIUS. Apply patches or updates from Arista if available. Limit concurrent authentication sessions and monitor for suspicious activity.

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