CVE-2026-89616: Linux Vulnerability (CVSS 7.5)

Description

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

0.37%

30.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 4342306f0f0d5ff4315a204d315c1b51b914fca5, < 7d60a4c49af4d5cb88aa7cbf998d0408bd415055; >= 4342306f0f0d5ff4315a204d315c1b51b914fca5, < cd40eee4923d104ebec9ac7513b971bc441e431d; >= 4342306f0f0d5ff4315a204d315c1b51b914fca5, < 77d8efd04745cda23858546afdbd9d07b591758e; >= 4342306f0f0d5ff4315a204d315c1b51b914fca5, < 0f699ddb290a24b37e1bc9bf1e3c9dbccf564bea; >= 4342306f0f0d5ff4315a204d315c1b51b914fca5, < 376ee45659a4b943df672ad275c63da00655f929; >= 4342306f0f0d5ff4315a204d315c1b51b914fca5, < 4a1b39b2e10eb8de86265e80cf2be4396bc1dce4; >= 4342306f0f0d5ff4315a204d315c1b51b914fca5, < 35d1ea92c7d946e2ebdbe36cdb2c969c8704bebd
Linux	Linux	5.15

References

Timeline

Published: Sep 11, 2026
Last Modified: Sep 14, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-89616?

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.

How severe is CVE-2026-89616?

CVE-2026-89616 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.37% probability of exploitation in the next 30 days.

How do I fix CVE-2026-89616?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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