# CVE-2026-74522: ksmbd: fix use-after-free in __close_file_table_ids()

> A use-after-free in the Linux kernel's ksmbd module allows attackers to execute arbitrary code or escalate privileges via crafted file operations.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** BELL-CVE-2026-74522, DEBIAN-CVE-2026-74522, GHSA-r5jm-2247-f5r8, UBUNTU-CVE-2026-74522

## What is CVE-2026-74522?

CVE-2026-74522 is a high-severity use after free vulnerability in Linux, published on 15 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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

ksmbd: fix use-after-free in __close_file_table_ids()

A ksmbd_file can remain alive after logical close while another session
holds a temporary reference obtained through ksmbd_lookup_fd_inode().
ksmbd_close_fd() currently marks the file closed and drops the idr-owned
reference, but leaves the pointer published in the closing session's idr
until the final reference is dropped.

If the foreign holder performs the final ksmbd_fd_put(), __put_fd_final()
supplies the foreign session's file table to __ksmbd_close_fd(). The object
is then freed without being removed from its owner's idr, and the owner
session later dereferences the stale pointer during file-table teardown.

Remove the volatile id from the owner's idr while ksmbd_close_fd() still
holds that table's lock, and clear volatile_id before dropping
the idr-owned reference. A later foreign final put then only performs
physical destruction and cannot remove the object from the wrong table.

## Which versions are affected by CVE-2026-74522?


## How do I fix CVE-2026-74522?

Apply the vendor's patch.

## Is CVE-2026-74522 being exploited?

There is no known exploitation of CVE-2026-74522 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74522 and fix it if it is affected.

What it is: CVE-2026-74522 is a high-severity use after free vulnerability in Linux, published on 15 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74522 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-2026-74522/ (Markdown: https://insights.sbomify.com/CVE-2026-74522/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74522
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74522
- OSV: https://osv.dev/vulnerability/CVE-2026-74522

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74522/
Summaries are generated and may contain mistakes; the official description above is the record.