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VulnerabilityPublished

CVE-2026-73444: Arista Networks EOS · Incorrect Implementation of Authentication Algorithm

Affects Arista Networks EOSSource CVE Database V5

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Not known to be exploited · CVSS 4.7 Medium · fixed in 4.36.2F : update Arista Networks EOS when convenient.

Data as of 30 Oct 2026, 20:25 UTC

CVSS 3.1 base score
4.7Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 22% 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:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 30 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

ProductAffectedFixed in
Arista NetworksEOSAffected
  • >=4.36.0 <4.36.2F
  • >=4.35.0 <4.35.6M
  • >=4.34.0 <4.34.8M
  • >=4.33.0 <4.33.10M
  • =0
Fixed in
  • 4.36.2F
  • 4.35.6M
  • 4.34.8M
  • 4.33.10M
Aristaarista/eospkg:rpm/arista/eosOther threatsAffected
  • >=4.33.0 <4.33.10M
  • >=4.34.0 <4.34.8M
  • >=4.35.0 <4.35.6M
  • >=4.36.0 <4.36.2F
  • =0
Fixed in
  • 4.33.10M
  • 4.34.8M
  • 4.35.6M
  • 4.36.2F

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, restrict layer 2 network access to trusted devices and monitor VRRP master role changes to detect potential unauthorized takeovers.

Description

CVE-2026-73444 is a vulnerability in Arista Networks EOS affecting VRRPv2 IP Authentication Header (IP-AH) authentication. An unauthenticated attacker with access to the layer 2 network segment running VRRP can bypass authentication and assume the virtual router master role. This allows the attacker to intercept, modify, or discard traffic sent to the virtual gateway address. The vulnerability affects specific versions of EOS prior to fixed releases. The CVSS score is 4.7, indicating medium severity with a focus on availability impact.

References

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