# CVE-2026-89617: fs/ntfs3: validate dirty page table on log replay

> A missing bounds check in the Linux kernel NTFS3 driver allows memory corruption during log replay, potentially leading to code execution or system crashes.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **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-100271, BELL-CVE-2026-89617, DEBIAN-CVE-2026-89617, GHSA-gfmm-7qwj-299m, UBUNTU-CVE-2026-89617

## What is CVE-2026-89617?

CVE-2026-89617 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: 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.

## Which versions are affected by CVE-2026-89617?


## How do I fix CVE-2026-89617?

Apply the vendor's patch.

## Is CVE-2026-89617 being exploited?

There is no known exploitation of CVE-2026-89617 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89617 and fix it if it is affected.

What it is: CVE-2026-89617 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-2026-89617 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-2026-89617/ (Markdown: https://insights.sbomify.com/CVE-2026-89617/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89617
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89617
- OSV: https://osv.dev/vulnerability/CVE-2026-89617

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89617/
Summaries are generated and may contain mistakes; the official description above is the record.