{
  "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 172 canonical URL",
        "url": "https://www.arista.com/en/support/advisories-notices/security-advisory/24728-security-advisory-0172"
      }
    ],
    "title": "Security Advisory 172",
    "tracking": {
      "current_release_date": "2026-09-17T11:48:22Z",
      "generator": {
        "engine": {
          "name": "Arista Networks SecEng Service CSAF Generator"
        }
      },
      "id": "Arista Networks Security Advisory 172",
      "initial_release_date": "2026-09-17T11:48:22Z",
      "revision_history": [
        {
          "date": "2026-09-17T11:48:22Z",
          "number": "1",
          "summary": "Document created"
        }
      ],
      "status": "interim",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "branches": [
                  {
                    "category": "product_version",
                    "name": "EOS version 4.34.8",
                    "product": {
                      "name": "EOS version 4.34.8",
                      "product_id": "CSAFPID-0"
                    }
                  },
                  {
                    "category": "product_version",
                    "name": "EOS version 4.33.10",
                    "product": {
                      "name": "EOS version 4.33.10",
                      "product_id": "CSAFPID-3"
                    }
                  },
                  {
                    "category": "product_version",
                    "name": "EOS version 4.35.6",
                    "product": {
                      "name": "EOS version 4.35.6",
                      "product_id": "CSAFPID-1"
                    }
                  },
                  {
                    "category": "product_version",
                    "name": "EOS version 1.0.0",
                    "product": {
                      "name": "EOS version 1.0.0",
                      "product_id": "CSAFPID-4"
                    }
                  },
                  {
                    "category": "product_version",
                    "name": "EOS version 4.36.2",
                    "product": {
                      "name": "EOS version 4.36.2",
                      "product_id": "CSAFPID-2"
                    }
                  }
                ],
                "category": "product_name",
                "name": "EOS"
              }
            ],
            "category": "product_family",
            "name": "Software Products"
          }
        ],
        "category": "vendor",
        "name": "Arista Networks, Inc."
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-73438",
      "id": {
        "system_name": "Arista Bug ID",
        "text": "1876199"
      },
      "notes": [
        {
          "category": "description",
          "text": "On affected platforms running Arista EOS with Open Shortest Path First version 3 (OSPFv3) configured, an unauthenticated attacker on the same OSPFv3 broadcast domain can send a specially crafted set of packets that can cause the Ospf3 agent to restart unexpectedly. The crash results in the loss of all OSPFv3 adjacencies on the affected device and may disrupt routing across the broader OSPF domain until the agent recovers.\n\nThis issue was reported externally by Dravanet Inc., and Arista is not aware of any malicious exploitation of this vulnerability in customer networks.",
          "title": "CVE Description"
        },
        {
          "category": "other",
          "text": "In order to be vulnerable to CVE-2026-73438, the following condition must be met:\n\nOSPFv3 must be configured:\n```switch>show ospfv3\nOSPFv3 address-family ipv4\nRouting Process \"ospfv3\" with ID 10.1.1.5 and Instance 64 VRF default\n...\nOSPFv3 address-family ipv6\nRouting Process \"ospfv3\" with ID 10.1.1.5 and Instance 0 VRF default\n...\n```\nor\n```\nswitch>show ipv6 ospf\nRouting Process \"ospfv3 0\" with ID 10.1.1.5 and Instance 0 VRF default\n...\n ```\nIf the commands produce no output, then OSPFv3 is not configured:\n```\nswitch>show ospfv3\nswitch>show ipv6 ospf\n```",
          "title": "1876199: Required Config for Exploitation"
        }
      ],
      "product_status": {
        "first_affected": [
          "CSAFPID-4"
        ],
        "fixed": [
          "CSAFPID-0",
          "CSAFPID-1",
          "CSAFPID-2",
          "CSAFPID-3"
        ]
      },
      "references": [
        {
          "category": "external",
          "summary": "MITRE",
          "url": "https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-73438"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Fixed in EOS version 4.33.10",
          "product_ids": [
            "CSAFPID-3"
          ]
        },
        {
          "category": "vendor_fix",
          "details": "Fixed in EOS version 4.34.8",
          "product_ids": [
            "CSAFPID-0"
          ]
        },
        {
          "category": "vendor_fix",
          "details": "Fixed in EOS version 4.35.6",
          "product_ids": [
            "CSAFPID-1"
          ]
        },
        {
          "category": "vendor_fix",
          "details": "Fixed in EOS version 4.36.2",
          "product_ids": [
            "CSAFPID-2"
          ]
        },
        {
          "category": "none_available",
          "details": "Not fixed in EOS version 1.0.0",
          "product_ids": [
            "CSAFPID-4"
          ]
        },
        {
          "category": "mitigation",
          "details": "The OSPFv3 authentication feature helps to mitigate this vulnerability. OSPFv3 authentication prevents unauthorized actors from injecting crafted packets into the OSPF domain. Enabling it on all OSPFv3-speaking interfaces ensures that packets from unauthenticated senders are discarded before they can trigger this vulnerability."
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-2",
            "CSAFPID-3",
            "CSAFPID-0",
            "CSAFPID-4",
            "CSAFPID-1"
          ]
        }
      ],
      "title": "CVE-2026-73438"
    }
  ]
}