{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "f4530fa574df4d833506c53697ed1daa0d390bf4"
            },
            {
              "fixed": "a29e95fbc51e8a1b932773fd0e259b2080881443"
            },
            {
              "fixed": "5ae18d87a45698e8244d0fcba64c658c35a7dd3d"
            },
            {
              "fixed": "9127589aabdee588278e8d0d0bd3709a760a92c8"
            },
            {
              "fixed": "49eaf1403201357762d745a35882fb734107d763"
            },
            {
              "fixed": "fd25996f57a95d56bc568c89b4921edcf334b7d8"
            },
            {
              "fixed": "828fad4fd418bcdb9f5d66fec0d184c52a85ec31"
            },
            {
              "fixed": "a668fa160247d7bbe921548cb845f607b8b9305f"
            },
            {
              "fixed": "b72f0db64205d9ce462038ba995d5d31eff32dc1"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.6.0"
            },
            {
              "fixed": "5.10.261"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.212"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72421.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: fib: Don't ignore error route in local/main tables.\n\nWhen CONFIG_IP_MULTIPLE_TABLES is enabled but no rule is added,\nfib_lookup() performs route lookup directly on two tables.\n\nSince the first lookup does not properly bail out, the result\nof an error route in the merged local/main table could be\noverwritten by another route in the default table:\n\n  # unshare -n\n  # ip link set lo up\n  # ip route add 192.168.0.0/24 dev lo table 253\n  # ip route add unreachable 192.168.0.0/24\n  # ip route get 192.168.0.1\n  192.168.0.1 dev lo table default uid 0\n      cache \u003clocal\u003e\n\nOnce a random rule is added, the error route is respected:\n\n  # ip rule add table 0\n  # ip rule del table 0\n  # ip route get 192.168.0.1\n  RTNETLINK answers: No route to host\n\nLet's fix the inconsistent behaviour.",
  "id": "CVE-2026-72421",
  "modified": "2026-08-18T03:31:20.184612145Z",
  "published": "2026-08-15T05:56:40.466Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/49eaf1403201357762d745a35882fb734107d763"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5ae18d87a45698e8244d0fcba64c658c35a7dd3d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/828fad4fd418bcdb9f5d66fec0d184c52a85ec31"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9127589aabdee588278e8d0d0bd3709a760a92c8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a29e95fbc51e8a1b932773fd0e259b2080881443"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a668fa160247d7bbe921548cb845f607b8b9305f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b72f0db64205d9ce462038ba995d5d31eff32dc1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fd25996f57a95d56bc568c89b4921edcf334b7d8"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72421.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72421"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ipv4: fib: Don't ignore error route in local/main tables."
}