CVE-2026-121368: Arista Networks EOS · Out-of-bounds Write
Affects Arista Networks EOSSource CVE Database V5
Not known to be exploited · CVSS 8.6 High : upgrade to 4.33.0F or 4.32.0F soon.
Data as of 10 Nov 2026, 20:22 UTC
Thin evidence
One scorer or none| CNA (Arista) | CVSS 3.1 | 8.6 |
|---|---|---|
| CNA (Arista) | CVSS 4.0 | 8.9 |
- Patch
- Available – fixed in 4.33.0F, 4.32.0F
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/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
Fixed versions are available starting from 4.32.0F and 4.33.0F. Users should upgrade affected EOS versions to these or later releases to remediate the vulnerability. No vendor advisory content contradicts this; thus, patching is the recommended mitigation.
Description
CVE-2026-121368 is a high-severity vulnerability in Arista Networks EOS affecting versions from 1.0.0 up to 4.36.2F. It involves an out-of-bounds write triggered by specially crafted BFD packets when Bidirectional Forwarding Detection is configured with keyed MD5 or SHA1 authentication. An unauthenticated attacker with network adjacency can cause a system reboot, impacting availability.