# CVE-2026-74486: binfmt_misc: use exe_file_deny_write_access() for the interpreter clone

> A local attacker can cause a denial of service by making the binfmt_misc interpreter unwritable through repeated executions when pre-content watches are active.

- **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:** 15 Aug 2026
- **Updated:** 23 Aug 2026
- **Also known as:** BELL-CVE-2026-74486, DEBIAN-CVE-2026-74486, GHSA-jmvv-89q4-p2wr, UBUNTU-CVE-2026-74486

## What is CVE-2026-74486?

CVE-2026-74486 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: use exe_file_deny_write_access() for the interpreter clone

For MISC_FMT_OPEN_FILE entries load_misc_binary() clones the
registered interpreter file and denies write access to the clone via
plain deny_write_access(). The clone is installed as
bprm->interpreter and later released by the exec machinery through
exe_file_allow_write_access() which skips the i_writecount increment
for files with FMODE_FSNOTIFY_HSM set.

The deny and allow side can therefore come to different conclusions
when pre-content watches are in play: if a pre-content watch is added
to the interpreter after registration every subsequent exec through
that entry takes a write denial on the clone that is never paired
with a write allowance, driving the interpreter inode's i_writecount
further down with each exec and leaving the interpreter unwritable
even after the entry and all its users are gone.

Take the write denial via exe_file_deny_write_access() so both sides
of the pairing base their decision on the same file mode, and
propagate failure instead of silently ignoring it: an interpreter
that is concurrently open for writing now fails the exec with
ETXTBSY, exactly like an interpreter freshly opened via open_exec()
would.

## Which versions are affected by CVE-2026-74486?


## How do I fix CVE-2026-74486?

Apply the vendor's patch.

## Is CVE-2026-74486 being exploited?

There is no known exploitation of CVE-2026-74486 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74486 and fix it if it is affected.

What it is: CVE-2026-74486 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-2026-74486 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-2026-74486/ (Markdown: https://insights.sbomify.com/CVE-2026-74486/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74486
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74486
- OSV: https://osv.dev/vulnerability/CVE-2026-74486

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74486/
Summaries are generated and may contain mistakes; the official description above is the record.