# CVE-2026-89779: fs/ntfs3: validate ef->size covers the record's name and value

> A local attacker can leak heap memory by mounting a crafted NTFS image, exploiting a missing size validation in the Linux kernel's NTFS3 driver.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101265, BELL-CVE-2026-89779, DEBIAN-CVE-2026-89779, GHSA-gg5m-j9gf-rmhm, UBUNTU-CVE-2026-89779

## What is CVE-2026-89779?

CVE-2026-89779 is a critical vulnerability in Linux, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

fs/ntfs3: validate ef->size covers the record's name and value

When an EA record has a non-zero ef->size, ntfs_read_ea() only checks
that the record fits in the remaining buffer (ea_size > bytes), not that
ef->size is large enough to hold the record's own name_len + 1 + elength.

A crafted image can pass validation with, e.g., ef->size = 24 but
elength = 0xffff. ntfs_get_ea() then trusts elength and copies it out of
the undersized record, reading past the kmalloc(info->size) allocation
and leaking heap memory to userspace via getxattr():

 BUG: KASAN: slab-out-of-bounds in ntfs_get_ea (fs/ntfs3/xattr.c:302)
 Read of size 65535 at addr ffff888100794550 by task exploit
  __asan_memcpy (mm/kasan/shadow.c:105)
  ntfs_get_ea (fs/ntfs3/xattr.c:302)
  ntfs_getxattr (fs/ntfs3/xattr.c:848)
  __vfs_getxattr (fs/xattr.c:441)
  vfs_getxattr (fs/xattr.c:474)
  do_getxattr (fs/xattr.c:800)
  path_getxattrat (fs/xattr.c:868)
  do_syscall_64 (arch/x86/entry/syscall_64.c:94)

 The buggy address is located 80 bytes inside of
  allocated 84-byte region in cache kmalloc-96

Compute the size the record needs and require ef->size to cover it.

## Which versions are affected by CVE-2026-89779?


## How do I fix CVE-2026-89779?

Apply the vendor's patch.

## Is CVE-2026-89779 being exploited?

There is no known exploitation of CVE-2026-89779 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89779 and fix it if it is affected.

What it is: CVE-2026-89779 is a critical vulnerability in Linux, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-89779 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-2026-89779/ (Markdown: https://insights.sbomify.com/CVE-2026-89779/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89779
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89779
- OSV: https://osv.dev/vulnerability/CVE-2026-89779

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89779/
Summaries are generated and may contain mistakes; the official description above is the record.