{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "0ac32b8affb5a384253dbb8339bd2d0e91add0b7"
            },
            {
              "fixed": "aba546061341b56e9ffb37e1eb661a3628b6ec12"
            },
            {
              "fixed": "1e8da792672481d603fa7cd0d815577220a3ee27"
            },
            {
              "fixed": "708033c231bd782858f4ddbb46ee874a5a5fbdab"
            },
            {
              "fixed": "bbe03ad3fb9e714191757ca7b41582f930be7be2"
            },
            {
              "fixed": "1bfe9fb5ed2667fb075682408b776b5273162615"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.18.0"
            },
            {
              "fixed": "6.6.131"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.80"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.21"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31458.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: check contexts-\u003enr before accessing contexts_arr[0]\n\nMultiple sysfs command paths dereference contexts_arr[0] without first\nverifying that kdamond-\u003econtexts-\u003enr == 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-\u003econtexts-\u003enr == 0).\n\n    # damo start\n    # cd /sys/kernel/mm/damon/admin/kdamonds/0\n    # echo 0 \u003e contexts/nr_contexts\n\nThen, each of below commands will cause the NULL pointer dereference.\n\n    # echo update_schemes_stats \u003e state\n    # echo update_schemes_tried_regions \u003e state\n    # echo update_schemes_tried_bytes \u003e state\n    # echo update_schemes_effective_quotas \u003e state\n    # echo update_tuned_intervals \u003e state\n\nGuard all commands (except OFF) at the entry point of\ndamon_sysfs_handle_cmd().",
  "id": "CVE-2026-31458",
  "modified": "2026-07-08T05:36:11.001616060Z",
  "published": "2026-04-22T13:53:50.883Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1bfe9fb5ed2667fb075682408b776b5273162615"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1e8da792672481d603fa7cd0d815577220a3ee27"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/708033c231bd782858f4ddbb46ee874a5a5fbdab"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aba546061341b56e9ffb37e1eb661a3628b6ec12"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bbe03ad3fb9e714191757ca7b41582f930be7be2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31458.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31458"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "summary": "mm/damon/sysfs: check contexts-\u003enr before accessing contexts_arr[0]"
}