What’s Vulnerable › Vulnerabilities

CVE-2021-28510: For certain systems running EOS, a Precision Time Protocol (PTP) packet of a management/signaling message with an invalid Type-Length-Value (TLV) causes the PTP agent to restart. Repeated restarts of the service will make the service unavailable.

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2023-01-26 · updated 2026-06-17
• Weakness: CWE-400

Description

For certain systems running EOS, a Precision Time Protocol (PTP) packet of a management/signaling message with an invalid Type-Length-Value (TLV) causes the PTP agent to restart. Repeated restarts of the service will make the service unavailable.

Affected products

• Arista Networks EOS: before 4.23.10; from 4.24.0 before 4.24.8; from 4.25.0 before 4.25.6; from 4.26.0 before 4.26.4; from 4.27.0 before 4.27.1 — fixed in 4.23.10, 4.24.8, 4.25.6, 4.26.4, 4.27.1

How to fix

Upgrade to a fixed version: Arista Networks EOS 4.23.10, 4.24.8, 4.25.6, 4.26.4. Check the vendor advisory for mitigations.

References

• https://www.arista.com/en/support/advisories-notices/security-advisory/15439-security-advisory-0076
• https://www.arista.com/en/support/advisories-notices/security-advisory/15439-security-advisory-0076

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