# CVE-2026-97949: configfs: unhash the dentry before dropping the item in rmdir

> A use-after-free in the Linux kernel configfs subsystem allows local attackers to execute arbitrary code or escalate privileges via a race condition during directory removal.

- **Severity:** Not scored
- **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:** 25 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-104555, BELL-CVE-2026-97949, DEBIAN-CVE-2026-97949, GHSA-gmrw-x43x-r9qf, UBUNTU-CVE-2026-97949

## What is CVE-2026-97949?

CVE-2026-97949 is an use after free vulnerability in Linux, published on 25 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:

configfs: unhash the dentry before dropping the item in rmdir

configfs_get_config_item() treats a hashed dentry as proof that
sd->s_element is a live config_item.  configfs_rmdir() breaks that:
simple_rmdir() leaves the dentry hashed, the last reference to the item is
dropped right after, and the dentry is only unhashed by d_delete() once
->rmdir() has returned.  configfs_symlink() resolves its target holding no
lock on it, so get_target() can land in that window:

  BUG: KASAN: slab-use-after-free in config_item_get+0x26/0x90
   get_target fs/configfs/symlink.c:128 [inline]
   configfs_symlink+0x4ab/0x1030 fs/configfs/symlink.c:185

Unhash in configfs_remove_dir(), while the item is still guaranteed to be
there.  A reference obtained just before that stays harmless, as
create_link() rechecks CONFIGFS_USET_DROPPING, already set by
configfs_detach_prep().  Both configfs_unregister_subsystem() paths
d_drop() after detaching, so this only makes rmdir match them.

## Which versions are affected by CVE-2026-97949?


## How do I fix CVE-2026-97949?

Apply the vendor's patch.

## Is CVE-2026-97949 being exploited?

There is no known exploitation of CVE-2026-97949 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97949 and fix it if it is affected.

What it is: CVE-2026-97949 is an use after free vulnerability in Linux, published on 25 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-2026-97949 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-2026-97949/ (Markdown: https://insights.sbomify.com/CVE-2026-97949/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97949
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97949
- OSV: https://osv.dev/vulnerability/CVE-2026-97949

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97949/
Summaries are generated and may contain mistakes; the official description above is the record.