CVE-2026-121290: Arista Networks EOS · Unprotected Alternate Channel
Affects Arista Networks EOSSource CVE Database V5
Not known to be exploited · CVSS 8.2 High : upgrade to 4.33.0F or 4.32.0F soon.
Data as of 10 Nov 2026, 20:32 UTC
Thin evidence
One scorer or none| CNA (Arista) | CVSS 3.1 | 8.2 |
|---|---|---|
| CNA (Arista) | CVSS 4.0 | 8.3 |
- Patch
- Available – fixed in 4.33.0F, 4.32.0F
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:HExploitation evidence
Disclosed: evidence found.
CVE published 10 Nov 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 10 Nov 2026.
What to do
Upgrade Arista Networks EOS to 4.33.0F or 4.32.0F.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Arista NetworksEOS | Affected
| Fixed in
|
AI-suggested
A fix is available in Arista EOS versions 4.32.0F and 4.33.0F and later. Users should upgrade to these or later versions to remediate the vulnerability. Since this is not a cloud service, manual patching is required. No additional mitigation steps are indicated by the vendor advisory.
Description
CVE-2026-121290 is a vulnerability in Arista Networks EOS affecting Border Gateway Protocol (BGP) configurations. Changing the BGP listen port from its default disables the default protective Access Control List (ACL) rules that guard against unexpected BGP peering attempts. This can lead to unauthorized BGP connections, potentially impacting system availability.