CVE-2026-73443: Arista Networks EOS · Authentication Bypass by Capture-replay
Affects Arista Networks EOSSource CVE Database V5
Not known to be exploited · CVSS 4.7 Medium · fixed in 4.36.2F : update Arista Networks EOS when convenient.
Data as of 31 Oct 2026, 20:20 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 19% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.36.2F, 4.35.6M, 4.34.8M +1
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:LExploitation evidence
Disclosed: evidence found.
CVE published 16 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.
What to do
Upgrade EOS and arista/eos to 4.36.2F, 4.35.6M, 4.34.8M or 4.33.10M.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Arista NetworksEOS | Affected
| Fixed in
|
| Arista NetworksEOS | Affected
| Fixed in
|
| Arista NetworksEOS | Affected
| Fixed in
|
| Arista NetworksEOS | Affected
| Fixed in
|
Aristaarista/eospkg:rpm/arista/eosOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, network administrators should consider network segmentation or other controls to limit attacker access to the layer 2 segment where VRRP is running.
Description
CVE-2026-73443 is an authentication bypass vulnerability in Arista Networks EOS affecting VRRPv2 IP-AH authentication. An unauthenticated attacker on the same layer 2 network segment can capture and replay legitimate VRRP advertisements indefinitely. This replay can cause stale VRRP state to be advertised, preventing backup routers from taking over the virtual gateway after the master router fails, resulting in denial of service for hosts relying on the virtual gateway.