November 13, 2026

CVE Watchtower

CVE-2026-121295Arista Networks EOS

NVD

Vulnerability Summary

On affected platforms running Arista EOS configured as S-BFD peers, an unauthenticated attacker could send a crafted S-BFD PDU to an initiator device. This crafted PDU could cause the kernel on the initiator device to crash, resulting in an unexpected device reboot.
Severity Level
CRITICAL(9.2)
Published Date
Nov 10, 2026
Last Modified
Nov 13, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
0.46%Probability
Root Weakness (CWE)
CWE-1284 ↗
See the MITRE CWE entry for the full definition of this weakness.
CVSS v4.0 Base Metrics — Score 9.2 (CRITICAL)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
Attack VectorNetwork
Attack ComplexityLow
Attack RequirementsNone
Privileges RequiredNone
User InteractionNone
Confidentiality (Vulnerable System)None
Integrity (Vulnerable System)None
Availability (Vulnerable System)High
Confidentiality (Subsequent System)None
Integrity (Subsequent System)None
Availability (Subsequent System)High
Show CVSS v3.x metrics (score 8.6)
CVSS v3.1 Base Metrics — Score 8.6 (HIGH)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeChanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh

Affected & Patched Versions

Affected Versions
  • Arista Networks EOS >= 4.36.0F and <= 4.36.2F
  • Arista Networks EOS >= 4.35.0F and <= 4.35.6M
  • Arista Networks EOS >= 4.34.0F and <= 4.34.8M
  • Arista Networks EOS >= 4.33.0F and <= 4.33.10M
  • Arista Networks EOS >= 4.32.0F and < 4.33.0F
  • Arista Networks EOS >= 1.0.0 and < 4.32.0F
Patched Versions
  • Arista Networks EOS 4.36.2F
  • Arista Networks EOS 4.35.6M
  • Arista Networks EOS 4.34.8M
  • Arista Networks EOS 4.33.10M
  • Arista Networks EOS 4.33.0F
  • Arista Networks EOS 4.32.0F

What to do

Plan remediation soon. No exploitation is confirmed yet, but the severity is critical.

  1. Check whether you run Arista Networks EOS and which version.
  2. Update to a patched version listed above, then confirm the new version.

Timeline

  • Nov 10, 2026Published
  • Nov 13, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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External References

Data last checked: Nov 13, 2026 18:23 UTC