FKIE_CVE-2026-63817

Vulnerability from fkie_nvd - Published: 2026-07-19 12:16 - Updated: 2026-07-20 15:16
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: f2fs: validate compress cache inode only when enabled F2FS_COMPRESS_INO() uses NM_I(sbi)->max_nid as the synthetic inode number for the compressed page cache inode. That inode only exists when the compress_cache mount option is enabled. When compress_cache is disabled, max_nid is outside the valid inode range. A corrupted directory entry that points to ino == max_nid should therefore be rejected by f2fs_check_nid_range(). However, is_meta_ino() currently treats F2FS_COMPRESS_INO() as a meta inode unconditionally, so f2fs_iget() bypasses do_read_inode() and its nid range check, and instantiates a fake internal inode instead. Gate the compressed cache inode case on COMPRESS_CACHE, matching f2fs_init_compress_inode(). With compress_cache disabled, ino == max_nid now follows the normal inode path and is rejected as an out-of-range nid.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0969926d987bbde9a1aa49da317582ba37095805
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/13e4b59d3a9413f66f116fa6c4828519b960a5ea
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/16161444c30d8dff9428abbae42b72ce4e32a932
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/29115b8c9172d34e67ab26cc4f6c209b7a236d7a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5073c66a96a9c23c0c2533ed4ed06e42f9021208
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/77f216ff9ce5cde8eed9f6d12707e906dffdc9f7
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/inode.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "29115b8c9172d34e67ab26cc4f6c209b7a236d7a",
              "status": "affected",
              "version": "6ce19aff0b8cd386860855185c6cd79337fc4d2b",
              "versionType": "git"
            },
            {
              "lessThan": "13e4b59d3a9413f66f116fa6c4828519b960a5ea",
              "status": "affected",
              "version": "6ce19aff0b8cd386860855185c6cd79337fc4d2b",
              "versionType": "git"
            },
            {
              "lessThan": "16161444c30d8dff9428abbae42b72ce4e32a932",
              "status": "affected",
              "version": "6ce19aff0b8cd386860855185c6cd79337fc4d2b",
              "versionType": "git"
            },
            {
              "lessThan": "77f216ff9ce5cde8eed9f6d12707e906dffdc9f7",
              "status": "affected",
              "version": "6ce19aff0b8cd386860855185c6cd79337fc4d2b",
              "versionType": "git"
            },
            {
              "lessThan": "0969926d987bbde9a1aa49da317582ba37095805",
              "status": "affected",
              "version": "6ce19aff0b8cd386860855185c6cd79337fc4d2b",
              "versionType": "git"
            },
            {
              "lessThan": "5073c66a96a9c23c0c2533ed4ed06e42f9021208",
              "status": "affected",
              "version": "6ce19aff0b8cd386860855185c6cd79337fc4d2b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a23706426da9b611be5beae0f3faa260fb453b4e",
              "versionType": "git"
            },
            {
              "lessThan": "5.14",
              "status": "affected",
              "version": "5.13.19",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/inode.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.14"
            },
            {
              "lessThan": "5.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.177",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.144",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.95",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.38",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: validate compress cache inode only when enabled\n\nF2FS_COMPRESS_INO() uses NM_I(sbi)-\u003emax_nid as the synthetic inode\nnumber for the compressed page cache inode. That inode only exists when\nthe compress_cache mount option is enabled.\n\nWhen compress_cache is disabled, max_nid is outside the valid inode\nrange. A corrupted directory entry that points to ino == max_nid should\ntherefore be rejected by f2fs_check_nid_range(). However, is_meta_ino()\ncurrently treats F2FS_COMPRESS_INO() as a meta inode unconditionally,\nso f2fs_iget() bypasses do_read_inode() and its nid range check, and\ninstantiates a fake internal inode instead.\n\nGate the compressed cache inode case on COMPRESS_CACHE, matching\nf2fs_init_compress_inode(). With compress_cache disabled, ino ==\nmax_nid now follows the normal inode path and is rejected as an\nout-of-range nid."
    }
  ],
  "id": "CVE-2026-63817",
  "lastModified": "2026-07-20T15:16:48.577",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-19T12:16:54.757",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0969926d987bbde9a1aa49da317582ba37095805"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/13e4b59d3a9413f66f116fa6c4828519b960a5ea"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/16161444c30d8dff9428abbae42b72ce4e32a932"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/29115b8c9172d34e67ab26cc4f6c209b7a236d7a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5073c66a96a9c23c0c2533ed4ed06e42f9021208"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/77f216ff9ce5cde8eed9f6d12707e906dffdc9f7"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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