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CVE-2026-121367VulnerabilityPublished

On affected Arista EOS platforms with Routing Information Protocol version 2 (RIPv2) configured, under certain

Source GCVE Database

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Authoritative record:CVE-2026-121367· Critical 9.6

Not known to be exploited · CVSS 9.6 Critical : upgrade to 4.33.0F as a priority.

Data as of 10 Nov 2026, 23:17 UTC

CVSS 3.1 base score
9.6Critical
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Arista)CVSS 3.19.6
CNA (Arista)CVSS 4.06.1
Patch
Available – fixed in 4.33.0F
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Nov 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 10 Nov 2026.

What to do

Upgrade EOS to 4.33.0F.

Affected software

ProductAffectedFixed in
Arista NetworksEOSAffected
  • >=1.0.0 <4.33.0F
  • >=4.33.0F <=4.33.10M
  • >=4.34.0F <=4.34.8M
  • >=4.35.0F <=4.35.6M
  • >=4.36.0F <=4.36.2F
  • =4.37.0F
Fixed in
  • 4.33.0F

AI-suggested

If you cannot patch yet, restrict access to management interfaces and adjacent networks to trusted entities only, and monitor for unexpected RIPv2 route advertisements. Do not rely on the RIP agent's configuration alone to disable RIPv2 on management interfaces.

Description

A vulnerability in certain Arista EOS platforms with RIPv2 configured can cause RIPv2 to be silently enabled on management interfaces even when intended to be disabled. This allows unauthenticated attackers on adjacent networks to send crafted RIPv2 route advertisements to the device's management IP, potentially causing traffic redirection, blackholing, or network disruption.

References

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