FKIE_CVE-2025-40205

Vulnerability from fkie_nvd - Published: 2025-11-12 22:15 - Updated: 2026-10-19 21:10
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: btrfs: avoid potential out-of-bounds in btrfs_encode_fh() The function btrfs_encode_fh() does not properly account for the three cases it handles. Before writing to the file handle (fh), the function only returns to the user BTRFS_FID_SIZE_NON_CONNECTABLE (5 dwords, 20 bytes) or BTRFS_FID_SIZE_CONNECTABLE (8 dwords, 32 bytes). However, when a parent exists and the root ID of the parent and the inode are different, the function writes BTRFS_FID_SIZE_CONNECTABLE_ROOT (10 dwords, 40 bytes). If *max_len is not large enough, this write goes out of bounds because BTRFS_FID_SIZE_CONNECTABLE_ROOT is greater than BTRFS_FID_SIZE_CONNECTABLE originally returned. This results in an 8-byte out-of-bounds write at fid->parent_root_objectid = parent_root_id. A previous attempt to fix this issue was made but was lost. https://lore.kernel.org/all/4CADAEEC020000780001B32C@vpn.id2.novell.com/ Although this issue does not seem to be easily triggerable, it is a potential memory corruption bug that should be fixed. This patch resolves the issue by ensuring the function returns the appropriate size for all three cases and validates that *max_len is large enough before writing any data.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0276c8582488022f057b4cec21975a5edf079f47
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/361d67276eb8ec6be8f27f4ad6c6090459438fee
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/43143776b0a7604d873d1a6f3e552a00aa930224
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/60de2f55d2aca53e81b4ef2a67d7cc9e1eb677db
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/742b44342204e5dfe3926433823623c1a0c581df
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d3a9a8e1275eb9b87f006b5562a287aea3f6885f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d91f6626133698362bba08fbc04bd72c466806d3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dff4f9ff5d7f289e4545cc936362e01ed3252742
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/export.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "60de2f55d2aca53e81b4ef2a67d7cc9e1eb677db",
              "status": "affected",
              "version": "be6e8dc0ba84029997075a1ec77b4ddb863cbe15",
              "versionType": "git"
            },
            {
              "lessThan": "742b44342204e5dfe3926433823623c1a0c581df",
              "status": "affected",
              "version": "be6e8dc0ba84029997075a1ec77b4ddb863cbe15",
              "versionType": "git"
            },
            {
              "lessThan": "d3a9a8e1275eb9b87f006b5562a287aea3f6885f",
              "status": "affected",
              "version": "be6e8dc0ba84029997075a1ec77b4ddb863cbe15",
              "versionType": "git"
            },
            {
              "lessThan": "d91f6626133698362bba08fbc04bd72c466806d3",
              "status": "affected",
              "version": "be6e8dc0ba84029997075a1ec77b4ddb863cbe15",
              "versionType": "git"
            },
            {
              "lessThan": "0276c8582488022f057b4cec21975a5edf079f47",
              "status": "affected",
              "version": "be6e8dc0ba84029997075a1ec77b4ddb863cbe15",
              "versionType": "git"
            },
            {
              "lessThan": "361d67276eb8ec6be8f27f4ad6c6090459438fee",
              "status": "affected",
              "version": "be6e8dc0ba84029997075a1ec77b4ddb863cbe15",
              "versionType": "git"
            },
            {
              "lessThan": "43143776b0a7604d873d1a6f3e552a00aa930224",
              "status": "affected",
              "version": "be6e8dc0ba84029997075a1ec77b4ddb863cbe15",
              "versionType": "git"
            },
            {
              "lessThan": "dff4f9ff5d7f289e4545cc936362e01ed3252742",
              "status": "affected",
              "version": "be6e8dc0ba84029997075a1ec77b4ddb863cbe15",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/export.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.29"
            },
            {
              "lessThan": "2.6.29",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.301",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.246",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.195",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.113",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.54",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "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\nbtrfs: avoid potential out-of-bounds in btrfs_encode_fh()\n\nThe function btrfs_encode_fh() does not properly account for the three\ncases it handles.\n\nBefore writing to the file handle (fh), the function only returns to the\nuser BTRFS_FID_SIZE_NON_CONNECTABLE (5 dwords, 20 bytes) or\nBTRFS_FID_SIZE_CONNECTABLE (8 dwords, 32 bytes).\n\nHowever, when a parent exists and the root ID of the parent and the\ninode are different, the function writes BTRFS_FID_SIZE_CONNECTABLE_ROOT\n(10 dwords, 40 bytes).\n\nIf *max_len is not large enough, this write goes out of bounds because\nBTRFS_FID_SIZE_CONNECTABLE_ROOT is greater than\nBTRFS_FID_SIZE_CONNECTABLE originally returned.\n\nThis results in an 8-byte out-of-bounds write at\nfid-\u003eparent_root_objectid = parent_root_id.\n\nA previous attempt to fix this issue was made but was lost.\n\nhttps://lore.kernel.org/all/4CADAEEC020000780001B32C@vpn.id2.novell.com/\n\nAlthough this issue does not seem to be easily triggerable, it is a\npotential memory corruption bug that should be fixed. This patch\nresolves the issue by ensuring the function returns the appropriate size\nfor all three cases and validates that *max_len is large enough before\nwriting any data."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nbtrfs: evita un potencial desbordamiento de l\u00edmites en btrfs_encode_fh()\n\nLa funci\u00f3n btrfs_encode_fh() no tiene en cuenta adecuadamente los tres casos que maneja.\n\nAntes de escribir en el descriptor de archivo (fh), la funci\u00f3n solo devuelve al usuario BTRFS_FID_SIZE_NON_CONNECTABLE (5 dwords, 20 bytes) o BTRFS_FID_SIZE_CONNECTABLE (8 dwords, 32 bytes).\n\nSin embargo, cuando existe un padre y el ID ra\u00edz del padre y el inodo son diferentes, la funci\u00f3n escribe BTRFS_FID_SIZE_CONNECTABLE_ROOT (10 dwords, 40 bytes).\n\nSi *max_len no es lo suficientemente grande, esta escritura se desborda porque BTRFS_FID_SIZE_CONNECTABLE_ROOT es mayor que BTRFS_FID_SIZE_CONNECTABLE devuelto originalmente.\n\nEsto resulta en una escritura fuera de l\u00edmites de 8 bytes en fid-\u003eparent_root_objectid = parent_root_id.\n\nSe hizo un intento previo para solucionar este problema, pero se perdi\u00f3.\n\nhttps://lore.kernel.org/all/4CADAEEC020000780001B32C@vpn.id2.novell.com/\n\nAunque este problema no parece ser f\u00e1cilmente activable, es un potencial error de corrupci\u00f3n de memoria que deber\u00eda ser corregido. Este parche resuelve el problema asegurando que la funci\u00f3n devuelva el tama\u00f1o apropiado para los tres casos y valida que *max_len sea lo suficientemente grande antes de escribir cualquier dato."
    }
  ],
  "id": "CVE-2025-40205",
  "lastModified": "2026-10-19T21:10:00.160",
  "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"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-40205",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-15T21:58:09.178444Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2025-11-12T22:15:47.773",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0276c8582488022f057b4cec21975a5edf079f47"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/361d67276eb8ec6be8f27f4ad6c6090459438fee"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/43143776b0a7604d873d1a6f3e552a00aa930224"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/60de2f55d2aca53e81b4ef2a67d7cc9e1eb677db"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/742b44342204e5dfe3926433823623c1a0c581df"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d3a9a8e1275eb9b87f006b5562a287aea3f6885f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d91f6626133698362bba08fbc04bd72c466806d3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dff4f9ff5d7f289e4545cc936362e01ed3252742"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Deferred"
}



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