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VulnerabilityPublished

CVE-2026-121292: Arista Networks EOS · Out-of-bounds Read

Affects Arista Networks EOSSource CVE Database V5

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Not known to be exploited · CVSS 8.2 High : upgrade to 4.33.0F soon.

Data as of 10 Nov 2026, 20:32 UTC

CVSS 3.1 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Arista)CVSS 3.18.2
CNA (Arista)CVSS 4.08.3
Patch
Available – fixed in 4.33.0F
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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.

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
  • >=4.24.0F <4.33.0F
  • =4.37.0F
Fixed in
  • 4.33.0F

AI-suggested

A fix is available starting from EOS version 4.33.0F. Users should upgrade affected EOS versions to 4.33.0F or later to remediate this vulnerability. No additional mitigation steps are indicated by the vendor advisory.

Description

CVE-2026-121292 is an out-of-bounds read vulnerability in Arista Networks EOS caused by a malformed Error Report. This flaw can lead EOS to read beyond packet boundaries, which may terminate the RPKI agent or expose unintended memory contents through logging. The vulnerability affects multiple versions of EOS up to 4.36.2F and 4.35.6M, with a fix available starting from version 4.33.0F. The CVSS score is 8.2, indicating a high severity impact primarily due to potential denial of service and limited confidentiality exposure.

References

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