CVE-2026-19655: Arista Networks EOS · Improper Input Validation
Affects Arista Networks EOSSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| Arista NetworksEOS | Affected
| Fixed in
|
| Arista NetworksEOS | Affected
| Fixed in
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| Arista NetworksEOS | Affected
| Fixed in
|
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.