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VulnerabilityPublished

CVE-2026-121370: Arista Networks EOS · Unthrottled Resource Allocation

Affects Arista Networks EOSSource CVE Database V5

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Not known to be exploited · CVSS 8.6 High · fixed in 4.33.0F : patch Arista Networks EOS soon.

Data as of 10 Nov 2026, 20:22 UTC

CVSS 3.1 base score
8.6High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Arista)CVSS 3.18.6
CNA (Arista)CVSS 4.09.2
Patch
Available – fixed in 4.33.0F, 4.32.0F, 4.31.0F +1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/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 Arista Networks EOS to 4.33.0F, 4.32.0F, 4.31.0F or 4.30.0F.

Affected software

ProductAffectedFixed in
Arista NetworksEOSAffected
  • >=4.34.0F <=4.34.1F
  • >=4.33.0F <=4.33.8M
  • >=4.32.0F <4.33.0F
  • >=4.31.0F <4.32.0F
  • >=4.30.0F <4.31.0F
  • >=4.29.2F <4.30.0F
Fixed in
  • 4.33.0F
  • 4.32.0F
  • 4.31.0F
  • 4.30.0F

AI-suggested

Upgrade affected Arista EOS devices to fixed versions 4.30.0F, 4.31.0F, 4.32.0F, or 4.33.0F or later. Since this is a software vulnerability, patching is the recommended and effective mitigation. No vendor advisory content contradicts this guidance.

Description

CVE-2026-121370 is a high-severity vulnerability in Arista Networks EOS affecting versions from 4.29.2F up to and including 4.34.1F. It involves improper allocation of resources without limits or throttling in the Precision Time Protocol (PTP) feature. An unauthenticated attacker with network access to a PTP-enabled port can cause a denial of service (DoS) by sending crafted traffic. The issue has been fixed in versions 4.30.0F, 4.31.0F, 4.32.0F, and 4.33.0F.

References

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