{
  "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-2026-72170",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-72170",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-08-15T05:53:36.332Z",
    "updatedAt": "2026-10-16T18:45:00.097Z",
    "importedAt": "2026-10-24T01:58:25.636Z",
    "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": "9p: skip nlink update in cacheless mode to fix WARN_ON",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\n9p: skip nlink update in cacheless mode to fix WARN_ON\n\nv9fs_dec_count() unconditionally calls drop_nlink() on regular files,\neven when the inode's nlink is already zero. In cacheless mode the\nclient refetches inode metadata from the server (the source of truth)\non every operation, so by the time v9fs_remove() returns, the locally\ncached nlink may already reflect the post-unlink value:\n\n  1. Client initiates unlink, server processes it and sets nlink to 0\n  2. Client refetches inode metadata (nlink=0) before unlink returns\n  3. Client's v9fs_remove() completes successfully\n  4. Client calls v9fs_dec_count() which calls drop_nlink() on nlink=0\n\nThis race is easily triggered under heavy unlink workloads, such as\nstress-ng's unlink stressor, producing the following warning:\n\n  WARNING: fs/inode.c:417 at drop_nlink+0x4c/0xc8\n  Call trace:\n   drop_nlink+0x4c/0xc8\n   v9fs_remove+0x1e0/0x250 [9p]\n   v9fs_vfs_unlink+0x20/0x38 [9p]\n   vfs_unlink+0x13c/0x258\n   ...\n\nIn cacheless mode the server is authoritative and the inode is on its\nway out, so locally adjusting nlink buys nothing. Skip v9fs_dec_count()\nentirely when neither CACHE_META nor CACHE_LOOSE is set, which both\navoids the warning and removes a class of nlink races (two concurrent\nunlinkers observing nlink > 0 and both calling drop_nlink()) that an\nnlink == 0 guard alone would only narrow rather than close.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "ac89b2ef9b55924bcf922251f043ba73a32d05bb",
              "status": "affected",
              "versionType": "git",
              "lessThan": "6086469f7d469549bfd070348b717a6e43736200"
            },
            {
              "version": "ac89b2ef9b55924bcf922251f043ba73a32d05bb",
              "status": "affected",
              "versionType": "git",
              "lessThan": "ab257019cb72f467b55c95384d99c94e3908b928"
            },
            {
              "version": "ac89b2ef9b55924bcf922251f043ba73a32d05bb",
              "status": "affected",
              "versionType": "git",
              "lessThan": "4ec4ebe40c82cb4c60756732f6593055d010c59c"
            },
            {
              "version": "ac89b2ef9b55924bcf922251f043ba73a32d05bb",
              "status": "affected",
              "versionType": "git",
              "lessThan": "a5a682b016ef5b5384e28f6d652d47a8f8e73d37"
            },
            {
              "version": "ac89b2ef9b55924bcf922251f043ba73a32d05bb",
              "status": "affected",
              "versionType": "git",
              "lessThan": "de79c3f3643841b8659a71958df7cf2a66bfd409"
            },
            {
              "version": "ac89b2ef9b55924bcf922251f043ba73a32d05bb",
              "status": "affected",
              "versionType": "git",
              "lessThan": "8d610017c992de705b304d3d727a6e3a86af6149"
            },
            {
              "version": "ac89b2ef9b55924bcf922251f043ba73a32d05bb",
              "status": "affected",
              "versionType": "git",
              "lessThan": "8faccac11e1369adddf5d80f4a45af93f13b2e1a"
            },
            {
              "version": "ac89b2ef9b55924bcf922251f043ba73a32d05bb",
              "status": "affected",
              "versionType": "git",
              "lessThan": "574aa0b4799470ac814479f1138d19efe6262255"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "4.17",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "4.17"
            },
            {
              "version": "5.10.266",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "version": "5.15.217",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "version": "6.1.184",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "version": "6.6.145",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.97",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.18.40",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "version": "7.1.5",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "version": "7.2",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}