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VulnerabilityPublished

CVE-2026-121286: Arista Networks EOS · NULL Pointer Dereference

Affects Arista Networks EOSSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium : upgrade to 4.33.0F or 4.32.0F when convenient.

Data as of 10 Nov 2026, 20:33 UTC

CVSS 3.1 base score
6.5Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Arista)CVSS 3.16.5
CNA (Arista)CVSS 4.06.0
Patch
Available – fixed in 4.33.0F, 4.32.0F
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/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 or 4.32.0F.

Affected software

ProductAffectedFixed in
Arista NetworksEOSAffected
  • >=4.36.0F <=4.36.2F
  • >=4.35.0F <=4.35.6M
  • >=4.34.0F <=4.34.8M
  • >=4.33.0F <=4.33.10M
  • >=4.32.0F <4.33.0F
  • >=4.22.1F <4.32.0F
Fixed in
  • 4.33.0F
  • 4.32.0F

AI-suggested

Fixed versions 4.32.0F and 4.33.0F and later are available and should be applied to remediate this vulnerability. Since this is not a cloud service, manual patching by updating to these fixed versions is required. There are no vendor advisories indicating that no action is needed or that the issue is already mitigated.

Description

CVE-2026-121286 is a vulnerability in Arista Networks EOS affecting devices configured with BGP Segment Routing Traffic Engineering (SR-TE) in a multi-agent routing model. A crafted BGP packet from a peer can cause a NULL pointer dereference, leading to a BGP process restart and disruption of all BGP sessions on the device. The issue affects multiple EOS versions prior to 4.32.0F and 4.33.0F, where fixes are available.

References

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