{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2025-21731",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-21731",
    "idYear": 2025,
    "status": "PUBLISHED",
    "publishedAt": "2025-02-27T02:07:35.927Z",
    "updatedAt": "2026-10-15T01:03:51.467Z",
    "importedAt": "2026-10-24T01:57:29.455Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "nbd: don't allow reconnect after disconnect",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: don't allow reconnect after disconnect\n\nFollowing process can cause nbd_config UAF:\n\n1) grab nbd_config temporarily;\n\n2) nbd_genl_disconnect() flush all recv_work() and release the\ninitial reference:\n\n  nbd_genl_disconnect\n   nbd_disconnect_and_put\n    nbd_disconnect\n     flush_workqueue(nbd->recv_workq)\n    if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, ...))\n     nbd_config_put\n     -> due to step 1), reference is still not zero\n\n3) nbd_genl_reconfigure() queue recv_work() again;\n\n  nbd_genl_reconfigure\n   config = nbd_get_config_unlocked(nbd)\n   if (!config)\n   -> succeed\n   if (!test_bit(NBD_RT_BOUND, ...))\n   -> succeed\n   nbd_reconnect_socket\n    queue_work(nbd->recv_workq, &args->work)\n\n4) step 1) release the reference;\n\n5) Finially, recv_work() will trigger UAF:\n\n  recv_work\n   nbd_config_put(nbd)\n   -> nbd_config is freed\n   atomic_dec(&config->recv_threads)\n   -> UAF\n\nFix the problem by clearing NBD_RT_BOUND in nbd_genl_disconnect(), so\nthat nbd_genl_reconfigure() will fail.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "e70a578487a47d7cf058904141e586684d1c3381"
            },
            {
              "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "6bef6222a3f6c7adb6396f77f25a3579d821b09a"
            },
            {
              "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "e3be8862d73cac833e0fb7602636c19c6cb94b11"
            },
            {
              "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "e7343fa33751cb07c1c56b666bf37cfca357130e"
            },
            {
              "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "d208d2c52b652913b5eefc8ca434b0d6b757f68f"
            },
            {
              "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "a8ee6ecde2b7bfb58c8a3afe8a9d2b848f580739"
            },
            {
              "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "9793bd5ae4bdbdb2dde401a3cab94a6bfd05e302"
            },
            {
              "version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "844b8cdc681612ff24df62cdefddeab5772fadf1"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "4.12",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "4.12"
            },
            {
              "version": "5.4.291",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.4.*"
            },
            {
              "version": "5.10.235",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "version": "5.15.179",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "version": "6.1.129",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "version": "6.6.76",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.13",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.13.2",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.13.*"
            },
            {
              "version": "6.14",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}