Skip to main content
VulnerabilityPublished

CVE-2026-19655: Arista Networks EOS · Improper Input Validation

Affects Arista Networks EOSSource CVE Database V5

0
Compare

Not known to be exploited · CVSS 6.5 Medium · fixed in 4.35.6M : update Arista Networks EOS when convenient.

Data as of 30 Oct 2026, 20:25 UTC

CVSS 3.1 base score
6.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 4.35.6M, 4.34.8M, 4.33.10M
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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 Arista Networks EOS to 4.35.6M, 4.34.8M or 4.33.10M.

Affected software

ProductAffectedFixed in
Arista NetworksEOSAffected
  • >=4.35.0 <4.35.6M
Fixed in
  • 4.35.6M
Arista NetworksEOSAffected
  • >=4.34.0 <4.34.8M
Fixed in
  • 4.34.8M
Arista NetworksEOSAffected
  • >=4.33.0 <4.33.10M
Fixed in
  • 4.33.10M

AI-suggested

If you cannot patch yet, consider restricting access to client-facing VLANs or monitoring DHCP relay configurations to detect anomalous packets targeting Option 82. Avoid enabling DHCP relay features with Option 82 if not necessary.

Description

CVE-2026-19655 is a medium severity vulnerability in Arista Networks EOS affecting versions 4.33.0 through before 4.33.10M, 4.34.0 through before 4.34.8M, and 4.35.0 through before 4.35.6M. It involves improper input validation in the DHCP relay/snooping feature when configured with the information option (Option 82). An unauthenticated attacker on a client-facing VLAN where DHCP relay is configured can send a crafted packet that causes the DHCP Relay service to restart, resulting in denial of service.

References

Community reviews

Loading reviews…