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GHSA-486V-9MJ8-37C6

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-14 15:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: fix info-leak on partial LZNT decompress in ni_read_frame()

ni_read_frame() decompresses an LZNT $DATA frame into the vmapped target pages and then trusts decompress_lznt()'s return value:

unc_size = decompress_lznt(frame_ondisk, ondisk_size, frame_mem, frame_size); if ((ssize_t)unc_size < 0) err = unc_size; else if (!unc_size || unc_size > frame_size) err = -EINVAL;

decompress_lznt() stops as soon as the compressed stream is exhausted (e.g. a zero chunk header) and returns the number of bytes it actually wrote, which may be far less than frame_size. The bytes between unc_size and frame_size are never written. The only memset() that follows zeroes the region beyond i_valid; when the frame lies entirely within the file's valid size that memset() does not run, so the gap retains whatever was in the just-vmapped pages. All pages are then marked uptodate and returned to userspace, disclosing uninitialized (recently-freed) kernel page memory. A crafted compressed file whose stream decompresses to only a few bytes leaks the remainder of every frame on a plain read(2), which is enough to recover kernel pointers and defeat KASLR.

Zero the [unc_size, frame_size) tail immediately after a successful LZNT decompress so the remainder reads back as zero.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-89616"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:46Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: fix info-leak on partial LZNT decompress in ni_read_frame()\n\nni_read_frame() decompresses an LZNT $DATA frame into the vmapped target\npages and then trusts decompress_lznt()\u0027s return value:\n\n  unc_size = decompress_lznt(frame_ondisk, ondisk_size, frame_mem,\n                             frame_size);\n  if ((ssize_t)unc_size \u003c 0)        err = unc_size;\n  else if (!unc_size || unc_size \u003e frame_size)  err = -EINVAL;\n\ndecompress_lznt() stops as soon as the compressed stream is exhausted\n(e.g. a zero chunk header) and returns the number of bytes it actually\nwrote, which may be far less than frame_size. The bytes between unc_size\nand frame_size are never written. The only memset() that follows zeroes\nthe region beyond i_valid; when the frame lies entirely within the file\u0027s\nvalid size that memset() does not run, so the gap retains whatever was in\nthe just-vmapped pages. All pages are then marked uptodate and returned\nto userspace, disclosing uninitialized (recently-freed) kernel page\nmemory. A crafted compressed file whose stream decompresses to only a few\nbytes leaks the remainder of every frame on a plain read(2), which is\nenough to recover kernel pointers and defeat KASLR.\n\nZero the [unc_size, frame_size) tail immediately after a successful LZNT\ndecompress so the remainder reads back as zero.",
  "id": "GHSA-486v-9mj8-37c6",
  "modified": "2026-09-14T15:32:32Z",
  "published": "2026-09-11T21:31:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89616"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0f699ddb290a24b37e1bc9bf1e3c9dbccf564bea"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/35d1ea92c7d946e2ebdbe36cdb2c969c8704bebd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/376ee45659a4b943df672ad275c63da00655f929"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4a1b39b2e10eb8de86265e80cf2be4396bc1dce4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/77d8efd04745cda23858546afdbd9d07b591758e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7d60a4c49af4d5cb88aa7cbf998d0408bd415055"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cd40eee4923d104ebec9ac7513b971bc441e431d"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}



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