{
  "document": {
    "category": "security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "publisher": {
      "category": "vendor",
      "contact_details": "support@arista.com",
      "name": "Arista PSIRT",
      "namespace": "https://www.arista.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "Security advisory 224 canonical URL",
        "url": "https://www.arista.com/en/support/advisories-notices/security-advisory/25046-security-advisory-0224"
      }
    ],
    "title": "Security Advisory 224",
    "tracking": {
      "current_release_date": "2026-11-08T09:58:17Z",
      "generator": {
        "engine": {
          "name": "Arista Networks SecEng Service CSAF Generator"
        }
      },
      "id": "Arista Networks Security Advisory 224",
      "initial_release_date": "2026-11-08T09:58:17Z",
      "revision_history": [
        {
          "date": "2026-11-08T09:58:17Z",
          "number": "1",
          "summary": "Document created"
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "branches": [
                  {
                    "category": "product_version",
                    "name": "EOS version 4.34.2",
                    "product": {
                      "name": "EOS version 4.34.2",
                      "product_id": "CSAFPID-1"
                    }
                  },
                  {
                    "category": "product_version",
                    "name": "EOS version 4.33.9",
                    "product": {
                      "name": "EOS version 4.33.9",
                      "product_id": "CSAFPID-2"
                    }
                  },
                  {
                    "category": "product_version",
                    "name": "EOS version 4.29.2",
                    "product": {
                      "name": "EOS version 4.29.2",
                      "product_id": "CSAFPID-0"
                    }
                  }
                ],
                "category": "product_name",
                "name": "EOS"
              }
            ],
            "category": "product_family",
            "name": "Software Products"
          }
        ],
        "category": "vendor",
        "name": "Arista Networks, Inc."
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-121370",
      "id": {
        "system_name": "Arista Bug ID",
        "text": "1860051"
      },
      "notes": [
        {
          "category": "description",
          "text": "On affected platforms running Arista EOS with Precision Time Protocol (PTP) configured, an unauthenticated attacker with network access to a PTP-enabled port can create a denial of service (DoS) condition by sending traffic to the system.",
          "title": "CVE Description"
        },
        {
          "category": "other",
          "text": "PTP must be configured globally, and there must be at least one interface enabled, verify by running the below show command.\n```\nswitch>show ptp\nPTP Mode: Boundary Clock\nPTP Profile: Default ( IEEE1588 )\nClock Identity: XX:XX:XX:XX:XX:XX:XX:XX\nGrandmaster Clock Identity: XX:XX:XX:XX:XX:XX:XX:XX\nNumber of slave ports: 0\nNumber of master ports: 1\nOffset From Master (nanoseconds): 0\nMean Path Delay (nanoseconds): 0\nSteps Removed: 0\nSkew (estimated local-to-master clock frequency ratio): 1.0\n   Interface       State        Transport    Delay    \n                                             Mechanism\n--------------- ------------ --------------- ---------\n   Et1             Master       ipv4         e2e      \n```\n\nIf PTP is not configured there is no exposure to this issue and the message will look something like:\n```\nswitch>show ptp\nPTP Mode: Disabled\n```\n",
          "title": "1860051: Required Config for Exploitation"
        }
      ],
      "product_status": {
        "first_affected": [
          "CSAFPID-0"
        ],
        "fixed": [
          "CSAFPID-1",
          "CSAFPID-2"
        ]
      },
      "references": [
        {
          "category": "external",
          "summary": "MITRE CVE Entry",
          "url": "https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-121370"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Fixed in EOS version 4.33.9",
          "product_ids": [
            "CSAFPID-2"
          ]
        },
        {
          "category": "vendor_fix",
          "details": "Fixed in EOS version 4.34.2",
          "product_ids": [
            "CSAFPID-1"
          ]
        },
        {
          "category": "none_available",
          "details": "Not fixed in EOS version 4.29.2",
          "product_ids": [
            "CSAFPID-0"
          ]
        },
        {
          "category": "mitigation",
          "details": "A bandwidth limit can be applied to the PTP CPU queue to prevent CPU saturation by running the following commands in the privileged EOS CLI mode.\n```\nswitch# platform trident Linecard* diag mod MMU_MAX_BUCKET_QLAYER 1 1 THD_SEL=0x4d REFRESH=0x28\nswitch# platform trident Linecard* diag mod MMU_MIN_BUCKET_QLAYER 1 1 THD_SEL=0x10 REFRESH=0x8\n```\nNote: If PTP is currently enabled on any interfaces, disable it on those interfaces before running the mitigation commands, then re-enable it afterward. \n\nTo disable PTP on an interface, run the following command in the privileged EOS CLI configuration mode.\n```\nswitch(config-if)# no ptp enable\n```\nNote: These settings are not persistent. They must be re-applied after any forwarding plane reset or line card replacement.\n\nTo verify the results of these configurations, run the following commands in privileged EOS CLI:\n```\nswitch# platform trident Linecard* diag d chg MMU_MIN_BUCKET_QLAYER.mmu0 1 1\n```\nThe output should be similar to the following:\n```\nLinecard1/0 :\nMMU_MIN_BUCKET_QLAYER.mmu0[1]: <THD_SEL=0x10,REFRESH=8,>\nLinecard1/1 :\nMMU_MIN_BUCKET_QLAYER.mmu0[1]: <THD_SEL=0x10,REFRESH=8,>\n...\n```\nThen run:\n```\nswitch# platform trident Linecard* diag d chg MMU_MAX_BUCKET_QLAYER.mmu0 1 1\n```\nThe output should be similar to the following:\n```\nLinecard1/0 :\nMMU_MAX_BUCKET_QLAYER.mmu0[1]: <THD_SEL=0x4d,REFRESH=0x28,>\nLinecard1/1 :\nMMU_MAX_BUCKET_QLAYER.mmu0[1]: <THD_SEL=0x4d,REFRESH=0x28,>\n...\n```\nThe mitigation is correctly applied, if each line card slot listed produces exactly one output line and THD_SEL, and REFRESH matches the examples above.\n"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 8.6,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-2",
            "CSAFPID-1",
            "CSAFPID-0"
          ]
        }
      ],
      "title": "CVE-2026-121370"
    }
  ]
}