{
  "threat_severity" : "Moderate",
  "public_date" : "2026-05-27T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: ext4: don't set EXT4_GET_BLOCKS_CONVERT when splitting before submitting I/O",
    "id" : "2482002",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2482002"
  },
  "cvss3" : {
    "cvss3_base_score" : "7.0",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
    "status" : "draft"
  },
  "cwe" : "CWE-367",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\next4: don't set EXT4_GET_BLOCKS_CONVERT when splitting before submitting I/O\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.\nAssume we have an unwritten extent, and then DIO writes the second half.\n[UUUUUUUUUUUUUUUU] on-disk extent        U: unwritten extent\n[UUUUUUUUUUUUUUUU] extent status tree\n|<-   ->| ----> dio write this range\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.\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[0000000000SSSSSS]  data                S: stale data, 0: zeroed\n[WWWWWWWWWWWWWWWW]  on-disk extent      W: written extent\n[WWWWWWWWWWUUUUUU]  extent status tree\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.\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.", "A flaw was found in the Linux kernel's ext4 filesystem. When allocating blocks for direct I/O (DIO) and writeback, an incorrect flag handling during extent splitting could lead to a mismatch between the on-disk extent status and the extent status tree. This issue, particularly when a temporary error occurs during extent splitting, could result in the exposure of stale data to a local user if the direct I/O operation fails." ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Out of support scope",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-45985\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-45985\nhttps://lore.kernel.org/linux-cve-announce/2026052739-CVE-2026-45985-6195@gregkh/T" ],
  "name" : "CVE-2026-45985",
  "csaw" : false
}