IS-IS Link-State Database Purge Vulnerability in Arista EOS
CVE-2026-73459

7HIGH

Key Information:

Vendor

Arista Networks

Status
Eos
Vendor
CVE Published:
15 September 2026

What is CVE-2026-73459?

A vulnerability exists in Arista EOS that affects systems with IS-IS configured, allowing an unauthenticated attacker to inject a crafted IS-IS LSP PDU. This malicious action can cause legitimate link-state protocol information to be unexpectedly removed from the IS-IS link-state database, leading to potential traffic loss and network performance degradation. Preventative measures and timely updates are crucial to safeguard against such attacks.

Affected Version(s)

EOS 4.36.0 <= 4.36.1F

References

https://www.arista.com/en/support/advisories-notices/secu...
vendor-advisory

CVSS V4

Score:
7
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Adjacent Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

This issue was discovered internally by Arista and the company is not aware of any malicious uses of these issues in customer networks.
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