# CVE-2026-89617

## Summary

- **CVE ID:** CVE-2026-89617
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 14, 2026

## Description

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

fs/ntfs3: validate dirty page table on log replay

Each DIR_PAGE_ENTRY ends in a page_lcns[] array whose length is the on-disk
lcns_follow field. check_rstbl() validates the table bookkeeping but never
checks that this array fits in the entry, so a crafted lcns_follow lets the
v0->v1 conversion memmove and later replay passes run off the entry.

Add check_dp_table() to reject, right after check_rstbl(), any entry larger
than its size claims via struct_size() (the same expression used to allocate
these entries, so the check is overflow-safe by construction). All consumers
can then trust lcns_follow as the real capacity. This covers every
page_lcns[] access whose index is bounded by the entry itself (the
conversion memmove, the HotFix store via find_dp(), and the self-bounded
scan loops). Accesses whose index comes from the log record need a separate
bound and are handled in a follow-up patch.

## Affected Products

- Linux — Linux (b46acd6a6a627d876898e1c84d3f84902264b445)
- Linux — Linux (5.15)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)
- Linux — Linux (5.15.221)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)

## References

- [CNA](https://git.kernel.org/stable/c/1200c2779c43b62656ccbb67df9468a7a9af2484)
- [CNA](https://git.kernel.org/stable/c/2d94ffc9d7b5bb3517b129fe63b52d84bcd4ae56)
- [CNA](https://git.kernel.org/stable/c/0908da07c23be4f94b99dfd9a94765525f0fe4bd)
- [CNA](https://git.kernel.org/stable/c/006cb7713dec10368e699abc4367e5faa334c9a5)
- [CNA](https://git.kernel.org/stable/c/0e07ea2fc45a7b4757ef7bf1f692cc0180a08323)
- [CNA](https://git.kernel.org/stable/c/1e90b1703ee1a04cd3e9e399353fc536f5f3ba10)
- [CNA](https://git.kernel.org/stable/c/d23155634a4bc1183e761d5eb2c043b2e693cc98)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.14%
- **EPSS Percentile:** 3.6

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._