Bug 2532395 (CVE-2026-89616) - CVE-2026-89616 kernel: fs/ntfs3: fix info-leak on partial LZNT decompress in ni_read_frame()
Summary: CVE-2026-89616 kernel: fs/ntfs3: fix info-leak on partial LZNT decompress in ...
Keywords:
Status: NEW
Alias: CVE-2026-89616
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-11 22:45 UTC by OSIDB Bzimport
Modified: 2026-09-18 19:29 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
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Description OSIDB Bzimport 2026-09-11 22:45:21 UTC
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.


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