CVE-2026-45985 (GCVE-0-2026-45985)
Vulnerability from cvelistv5
Published
2026-05-27 12:18
Modified
2026-05-27 12:18
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: don't set EXT4_GET_BLOCKS_CONVERT when splitting before submitting I/O When allocating blocks during within-EOF DIO and writeback with dioread_nolock enabled, EXT4_GET_BLOCKS_PRE_IO was set to split an existing large unwritten extent. However, EXT4_GET_BLOCKS_CONVERT was set when calling ext4_split_convert_extents(), which may potentially result in stale data issues. Assume we have an unwritten extent, and then DIO writes the second half. [UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUUUUUU] extent status tree |<- ->| ----> dio write this range First, ext4_iomap_alloc() call ext4_map_blocks() with EXT4_GET_BLOCKS_PRE_IO, EXT4_GET_BLOCKS_UNWRIT_EXT and EXT4_GET_BLOCKS_CREATE flags set. ext4_map_blocks() find this extent and call ext4_split_convert_extents() with EXT4_GET_BLOCKS_CONVERT and the above flags set. Then, ext4_split_convert_extents() calls ext4_split_extent() with EXT4_EXT_MAY_ZEROOUT, EXT4_EXT_MARK_UNWRIT2 and EXT4_EXT_DATA_VALID2 flags set, and it calls ext4_split_extent_at() to split the second half with EXT4_EXT_DATA_VALID2, EXT4_EXT_MARK_UNWRIT1, EXT4_EXT_MAY_ZEROOUT and EXT4_EXT_MARK_UNWRIT2 flags set. However, ext4_split_extent_at() failed to insert extent since a temporary lack -ENOSPC. It zeroes out the first half but convert the entire on-disk extent to written since the EXT4_EXT_DATA_VALID2 flag set, but left the second half as unwritten in the extent status tree. [0000000000SSSSSS] data S: stale data, 0: zeroed [WWWWWWWWWWWWWWWW] on-disk extent W: written extent [WWWWWWWWWWUUUUUU] extent status tree Finally, if the DIO failed to write data to the disk, the stale data in the second half will be exposed once the cached extent entry is gone. Fix this issue by not passing EXT4_GET_BLOCKS_CONVERT when splitting an unwritten extent before submitting I/O, and make ext4_split_convert_extents() to zero out the entire extent range to zero for this case, and also mark the extent in the extent status tree for consistency.
References
Impacted products
Vendor Product Version
Linux Linux Version: b8a8684502a0fc852afa0056c6bb2a9273f6fcc0
Version: b8a8684502a0fc852afa0056c6bb2a9273f6fcc0
Version: b8a8684502a0fc852afa0056c6bb2a9273f6fcc0
Version: b8a8684502a0fc852afa0056c6bb2a9273f6fcc0
Version: b8a8684502a0fc852afa0056c6bb2a9273f6fcc0
Version: b8a8684502a0fc852afa0056c6bb2a9273f6fcc0
Version: b8a8684502a0fc852afa0056c6bb2a9273f6fcc0
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ext4/extents.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "77e407967cd872cd75d7e4a691908e49c8e6b4d4",
              "status": "affected",
              "version": "b8a8684502a0fc852afa0056c6bb2a9273f6fcc0",
              "versionType": "git"
            },
            {
              "lessThan": "37555690f39f78ef69af347d9aff897e07445949",
              "status": "affected",
              "version": "b8a8684502a0fc852afa0056c6bb2a9273f6fcc0",
              "versionType": "git"
            },
            {
              "lessThan": "67cdb7bd7442bd3cdc6d6088bbb2df9be2fe936c",
              "status": "affected",
              "version": "b8a8684502a0fc852afa0056c6bb2a9273f6fcc0",
              "versionType": "git"
            },
            {
              "lessThan": "2920ec61c98b9476781359f05b94da84e80f54d4",
              "status": "affected",
              "version": "b8a8684502a0fc852afa0056c6bb2a9273f6fcc0",
              "versionType": "git"
            },
            {
              "lessThan": "2698731d25823267c29190cb578da9296a0c0d7b",
              "status": "affected",
              "version": "b8a8684502a0fc852afa0056c6bb2a9273f6fcc0",
              "versionType": "git"
            },
            {
              "lessThan": "716e7439a5a9b18c3ff882c2f8c834b9ced1aaec",
              "status": "affected",
              "version": "b8a8684502a0fc852afa0056c6bb2a9273f6fcc0",
              "versionType": "git"
            },
            {
              "lessThan": "feaf2a80e78f89ee8a3464126077ba8683b62791",
              "status": "affected",
              "version": "b8a8684502a0fc852afa0056c6bb2a9273f6fcc0",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ext4/extents.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.15"
            },
            {
              "lessThan": "3.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.253",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.203",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.130",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.77",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.17",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.253",
                  "versionStartIncluding": "3.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.203",
                  "versionStartIncluding": "3.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.130",
                  "versionStartIncluding": "3.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.77",
                  "versionStartIncluding": "3.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.17",
                  "versionStartIncluding": "3.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.4",
                  "versionStartIncluding": "3.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "3.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: don\u0027t set EXT4_GET_BLOCKS_CONVERT when splitting before submitting I/O\n\nWhen allocating blocks during within-EOF DIO and writeback with\ndioread_nolock enabled, EXT4_GET_BLOCKS_PRE_IO was set to split an\nexisting large unwritten extent. However, EXT4_GET_BLOCKS_CONVERT was\nset when calling ext4_split_convert_extents(), which may potentially\nresult in stale data issues.\n\nAssume we have an unwritten extent, and then DIO writes the second half.\n\n   [UUUUUUUUUUUUUUUU] on-disk extent        U: unwritten extent\n   [UUUUUUUUUUUUUUUU] extent status tree\n            |\u003c-   -\u003e| ----\u003e dio write this range\n\nFirst, ext4_iomap_alloc() call ext4_map_blocks() with\nEXT4_GET_BLOCKS_PRE_IO, EXT4_GET_BLOCKS_UNWRIT_EXT and\nEXT4_GET_BLOCKS_CREATE flags set. ext4_map_blocks() find this extent and\ncall ext4_split_convert_extents() with EXT4_GET_BLOCKS_CONVERT and the\nabove flags set.\n\nThen, ext4_split_convert_extents() calls ext4_split_extent() with\nEXT4_EXT_MAY_ZEROOUT, EXT4_EXT_MARK_UNWRIT2 and EXT4_EXT_DATA_VALID2\nflags set, and it calls ext4_split_extent_at() to split the second half\nwith EXT4_EXT_DATA_VALID2, EXT4_EXT_MARK_UNWRIT1, EXT4_EXT_MAY_ZEROOUT\nand EXT4_EXT_MARK_UNWRIT2 flags set. However, ext4_split_extent_at()\nfailed to insert extent since a temporary lack -ENOSPC. It zeroes out\nthe first half but convert the entire on-disk extent to written since\nthe EXT4_EXT_DATA_VALID2 flag set, but left the second half as unwritten\nin the extent status tree.\n\n   [0000000000SSSSSS]  data                S: stale data, 0: zeroed\n   [WWWWWWWWWWWWWWWW]  on-disk extent      W: written extent\n   [WWWWWWWWWWUUUUUU]  extent status tree\n\nFinally, if the DIO failed to write data to the disk, the stale data in\nthe second half will be exposed once the cached extent entry is gone.\n\nFix this issue by not passing EXT4_GET_BLOCKS_CONVERT when splitting\nan unwritten extent before submitting I/O, and make\next4_split_convert_extents() to zero out the entire extent range\nto zero for this case, and also mark the extent in the extent status\ntree for consistency."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-27T12:18:43.844Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/77e407967cd872cd75d7e4a691908e49c8e6b4d4"
        },
        {
          "url": "https://git.kernel.org/stable/c/37555690f39f78ef69af347d9aff897e07445949"
        },
        {
          "url": "https://git.kernel.org/stable/c/67cdb7bd7442bd3cdc6d6088bbb2df9be2fe936c"
        },
        {
          "url": "https://git.kernel.org/stable/c/2920ec61c98b9476781359f05b94da84e80f54d4"
        },
        {
          "url": "https://git.kernel.org/stable/c/2698731d25823267c29190cb578da9296a0c0d7b"
        },
        {
          "url": "https://git.kernel.org/stable/c/716e7439a5a9b18c3ff882c2f8c834b9ced1aaec"
        },
        {
          "url": "https://git.kernel.org/stable/c/feaf2a80e78f89ee8a3464126077ba8683b62791"
        }
      ],
      "title": "ext4: don\u0027t set EXT4_GET_BLOCKS_CONVERT when splitting before submitting I/O",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-45985",
    "datePublished": "2026-05-27T12:18:43.844Z",
    "dateReserved": "2026-05-13T15:03:33.090Z",
    "dateUpdated": "2026-05-27T12:18:43.844Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.