{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-31458",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-31458"
  ],
  "published": "2026-04-22T13:57:42Z",
  "summary": "mm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]\n\nMultiple sysfs command paths dereference contexts_arr[0] without first\nverifying that kdamond->contexts->nr == 1.  A user can set nr_contexts to\n0 via sysfs while DAMON is running, causing NULL pointer dereferences.\n\nIn more detail, the issue can be triggered by privileged users like\nbelow.\n\nFirst, start DAMON and make contexts directory empty\n(kdamond->contexts->nr == 0).\n\n    # damo start\n    # cd /sys/kernel/mm/damon/admin/kdamonds/0\n    # echo 0 > contexts/nr_contexts\n\nThen, each of below commands will cause the NULL pointer dereference.\n\n    # echo update_schemes_stats > state\n    # echo update_schemes_tried_regions > state\n    # echo update_schemes_tried_bytes > state\n    # echo update_schemes_effective_quotas > state\n    # echo update_tuned_intervals > state\n\nGuard all commands (except OFF) at the entry point of\ndamon_sysfs_handle_cmd().",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": null,
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-31458"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/aba546061341b56e9ffb37e1eb661a3628b6ec12"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1e8da792672481d603fa7cd0d815577220a3ee27"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/708033c231bd782858f4ddbb46ee874a5a5fbdab"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/bbe03ad3fb9e714191757ca7b41582f930be7be2"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1bfe9fb5ed2667fb075682408b776b5273162615"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}