Is CVE-2026-121370 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-121370 being exploited in the wild.

How severe is CVE-2026-121370?

High severity, with a CVSS score of 8.6, published 10 November 2026.

Which products and versions are affected?

Arista Eos 4.34.1F and below (4.34.x), 4.33.8M and below (4.33.x), all 4.32.x, all 4.31.x, all 4.30.x, 4.29.2F and later (4.29.x End of Support).

How is CVE-2026-121370 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-121370?

Check whether you run Arista Eos at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-121370: Arista EOS denial of service in PTP

CVE-2026-121370 · Severity: high · CVSS 8.6 · Published 2026-11-10

Arista EOS is a network operating system used on switches and routing platforms. An attacker with network access to a Precision Time Protocol (PTP) port can send crafted traffic that exhausts the system's processing resources, causing a denial of service and preventing legitimate network traffic from being handled. This affects only 750X series switches with PTP enabled.

Technologies: Arista Eos. Vendors: Arista.

Quick answers

Is CVE-2026-121370 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-121370 being exploited in the wild.
How severe is CVE-2026-121370?: High severity, with a CVSS score of 8.6, published 10 November 2026.
Which products and versions are affected?: Arista Eos 4.34.1F and below (4.34.x), 4.33.8M and below (4.33.x), all 4.32.x, all 4.31.x, all 4.30.x, 4.29.2F and later (4.29.x End of Support).
Is there a fix for CVE-2026-121370?: No fixed version is recorded yet. A bandwidth limit can be applied to the PTP CPU queue by disabling PTP on affected interfaces, then running platform commands to set MMU_MAX_BUCKET_QLAYER and MMU_MIN_BUCKET_QLAYER thresholds. These settings are not persistent across forwarding plane resets or line card replacements.</anigation> <parameter name="timeline">[{"kind":"disclosed","at":"2026-11-10"}] If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-121370 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-121370?: Check whether you run Arista Eos at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

A bandwidth limit can be applied to the PTP CPU queue by disabling PTP on affected interfaces, then running platform commands to set MMU_MAX_BUCKET_QLAYER and MMU_MIN_BUCKET_QLAYER thresholds. These settings are not persistent across forwarding plane resets or line card replacements.</anigation> <parameter name="timeline">[{"kind":"disclosed","at":"2026-11-10"}]

Technical details

An unauthenticated attacker with network access to a PTP-enabled interface can trigger a resource exhaustion vulnerability (CWE-770) by sending traffic to the PTP CPU queue, causing high CPU utilization and preventing control-plane traffic processing. Exploitation requires PTP to be configured and at least one interface enabled globally. A bandwidth limit mitigation can be applied via CLI commands to throttle the PTP CPU queue.

Affected products

Arista EOS 4.34.1F and below (4.34.x), 4.33.8M and below (4.33.x), all 4.32.x, all 4.31.x, all 4.30.x, 4.29.2F and later (4.29.x End of Support)

References

https://www.arista.com/en/support/advisories-notices/security-advisory/25046-security-advisory-0224

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