On affected platforms running Arista EOS with VRRPv2 IP-AH authentication configured, an unauthenticated attacker within the same layer 2 network segment on which VRRP is running can capture a legitimate authenticated VRRP advertisement and replay it indef
Published Sep 16, 2026 · Updated Sep 17, 2026
On affected platforms running Arista EOS with VRRPv2 IP-AH authentication configured, an unauthenticated attacker within the same layer 2 network segment on which VRRP is running can capture a legitimate authenticated VRRP advertisement and replay it indefinitely. Replayed advertisements can be used to advertise stale VRRP state, for example to prevent a backup router from taking over the virtual gateway after the original master has gone down, resulting in a denial of service for hosts using the virtual gateway address.
Summary
What happened
On affected platforms running Arista EOS with VRRPv2 IP-AH authentication configured, an unauthenticated attacker within the same layer 2 network segment on which VRRP is running can capture a legitimate authenticated VRRP advertisement and replay it indefinitely. Replayed advertisements can be used to advertise stale VRRP state, for example to prevent a backup router from taking over the virtual gateway after the original master has gone down, resulting in a denial of service for hosts using the virtual gateway address.
The record
- CVE
- CVE-2026-73443
- Published
- Sep 16, 2026
- Updated
- Sep 17, 2026
- Vendor
- Arista Networks
- Product
- Arista EOS
- Classifications
- Unavailable
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 16, 2026CVE publishedPublication date reported by the CVE source.
- Sep 17, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.33.0 <=4.33.9M changes=[{"at":"4.33.10M","status":"unaffected"}]
- Affected versionversion=4.34.0 <=4.34.7M changes=[{"at":"4.34.8M","status":"unaffected"}]
- Affected versionversion=4.35.0 <=4.35.5M changes=[{"at":"4.35.6M","status":"unaffected"}]
- Affected versionversion=4.36.0 <=4.36.1F changes=[{"at":"4.36.2F","status":"unaffected"}]
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
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Technologies
Your stack
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Your stack
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