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

> A crafted NTFS log record can overflow the page_lcns array in the Linux kernel NTFS3 driver, potentially allowing local attackers to execute code or escalate privileges.

- **Severity:** High 8.4 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100625, BELL-CVE-2026-89615, DEBIAN-CVE-2026-89615, GHSA-r33c-hmhm-vc95, UBUNTU-CVE-2026-89615

## What is CVE-2026-89615?

CVE-2026-89615 is a high-severity memory corruption vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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]

## Which versions are affected by CVE-2026-89615?


## How do I fix CVE-2026-89615?

Apply the vendor's patch.

## Is CVE-2026-89615 being exploited?

There is no known exploitation of CVE-2026-89615 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89615 and fix it if it is affected.

What it is: CVE-2026-89615 is a high-severity memory corruption vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-89615 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-89615/ (Markdown: https://insights.sbomify.com/CVE-2026-89615/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89615
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89615
- OSV: https://osv.dev/vulnerability/CVE-2026-89615

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89615/
Summaries are generated and may contain mistakes; the official description above is the record.