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ext4: fix out-of-bounds read in ext4_read_inline_dir()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ext4: fix out-of-bounds read in ext4_read_inline_dir() ext4_read_inline_dir() can read a dirent header past the end of its inline buffer, triggering a slab-out-of-bounds read during getdents64(): BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry Read of size 2 at addr ffff88800f3dd23c by task exploit/148 ... __ext4_check_dir_entry ext4_read_inline_dir iterate_dir The dirent payload lives in a buffer of exactly inline_size bytes: dir_buf = kmalloc(inline_size, GFP_NOFS); but iteration runs in a position space extra_offset bytes larger (extra_size = extra_offset + inline_size) so the synthetic "." and ".." land at their block-dir offsets. A dirent is formed at "dir_buf + pos - extra_offset", yet the ext4_check_dir_entry() length argument uses the larger extra_size. A position whose dirent header would extend past extra_size is therefore accepted, and the rescan loop's rec_len probe and ext4_check_dir_entry() dereference de->rec_len before the entry is rejected. Reject a position whose minimum-size dirent header would not fit within extra_size before forming de, in both the rescan and main loops, and pass inline_size rather than extra_size to ext4_check_dir_entry() so the length check matches the physical buffer.

Announced Source revision 1
Original source ↗

CVE-2026-89786

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-89786

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572",
        "lessThan": "d1e7c186555ad65554fd2f2b02f5a539aa35ae48",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572",
        "lessThan": "5fd20d4e50dd6e460b3ea8e4396f8553d4526f8f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572",
        "lessThan": "1a1dea633b724a1c042dbcdb1fed27f410916688",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572",
        "lessThan": "b060861f662d4826dc700a1c3584243bb3474cfe",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572",
        "lessThan": "6702c7da86d8cdb88d0fc57166286e115ffeb8c0",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572",
        "lessThan": "36bf17bb90cdf7a623499b624b05acde4d2feef5",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d8b0235aa98f8c26bf94d308be3fdd24154572",
        "lessThan": "9333cc809f0a89e001b814155a6cb8903a6274df",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/ext4/inline.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "3.10"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "3.10",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.15.221",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.188",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.110",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.52",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/ext4/inline.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-89786

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#36256 · Revision 1
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Publisher date
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