# CVE-2026-74487: binfmt_misc: restore write access when removing an entry

> A local attacker with high privileges can cause a denial of service by preventing write access to interpreter binaries after removing binfmt_misc entries.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 23 Aug 2026
- **Also known as:** AZL-96344, BELL-CVE-2026-74487, DEBIAN-CVE-2026-74487, GHSA-fq4p-qqh8-rhh7, UBUNTU-CVE-2026-74487

## What is CVE-2026-74487?

CVE-2026-74487 is a denial of service vulnerability in Linux, published on 15 Aug 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:

binfmt_misc: restore write access when removing an entry

Registering an entry with the MISC_FMT_OPEN_FILE flag opens the
interpreter via open_exec() which denies write access to it for as
long as the entry exists. Removing the entry closes the interpreter
file via filp_close() but never restores write access, leaving the
inode's i_writecount permanently negative. Opening the interpreter
for writing keeps failing with ETXTBSY long after the entry is gone
until the inode is evicted from the inode cache.

Commit 90f601b497d7 ("binfmt_misc: restore write access before
closing files opened by open_exec()") fixed the same imbalance in the
error path of bm_register_write() but the actual removal path has
been leaking the write denial since the introduction of the flag.

Restore write access in put_binfmt_handler() before closing the
interpreter file.

## Which versions are affected by CVE-2026-74487?


## How do I fix CVE-2026-74487?

Apply the vendor's patch.

## Is CVE-2026-74487 being exploited?

There is no known exploitation of CVE-2026-74487 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74487 and fix it if it is affected.

What it is: CVE-2026-74487 is a denial of service vulnerability in Linux, published on 15 Aug 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-2026-74487 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-2026-74487/ (Markdown: https://insights.sbomify.com/CVE-2026-74487/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74487
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74487
- OSV: https://osv.dev/vulnerability/CVE-2026-74487

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74487/
Summaries are generated and may contain mistakes; the official description above is the record.