# CVE-2026-35373: uutils coreutils ln improper handling of non-UTF-8 filenames

Source: https://junglewise.ai/threats/cve-2026-35373-uutils-coreutils-ln-improper-handling-of-non-utf-8-filenames  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-22. Updated: 2026-07-06  
License: CC BY 4.0 with a link back

CVE-2026-35373 · Severity: low · CVSS 3.3 · Published 2026-04-22

The 'ln' utility in uutils coreutils, a Rust-based alternative to standard GNU command-line tools, fails to process filenames that contain non-UTF-8 characters when using the target-directory mode. This can cause automated scripts or system tasks to fail when they encounter valid but non-standard filenames on Unix systems. While it does not expose data, it can disrupt operations and lead to a local denial of service for specific file-linking tasks.

Technologies: [Uutils Coreutils](https://junglewise.ai/threats/technologies/uutils-coreutils). Vendors: [crates.io](https://junglewise.ai/threats/vendors/crates-io), [Uutils](https://junglewise.ai/threats/vendors/uutils).

## Quick answers

**Is CVE-2026-35373 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-35373 being exploited in the wild.

**How severe is CVE-2026-35373?** Low severity, with a CVSS score of 3.3, published 22 April 2026.

**Which products and versions are affected?** uu_ln (crates.io) < 0.6.0, SEMVER:introduced=0,fixed=0.6.0.

**Is there a fix for CVE-2026-35373?** Yes. uu_ln (crates.io): upgrade to 0.6.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-35373 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-35373?** Check whether you run uu_ln (crates.io) or Uutils Coreutils at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- uu_ln (crates.io): upgrade to 0.6.0 or later

  ```sh
  cargo update -p uu_ln
  ```


## Technical details

A logic error in the 'ln' utility (uu_ln) of uutils coreutils causes the program to enforce UTF-8 encoding on source paths when using target-directory forms (e.g., 'ln SOURCE... DIRECTORY'). This deviates from GNU behavior, which treats filenames as raw bytes. An attacker or a system environment with filenames containing non-UTF-8 bytes (such as 0xFF) will cause the utility to fail to 'stat' the file, resulting in a non-zero exit code and failure to create the link. This is classified as CWE-176 (Improper Handling of Unicode Encoding). The issue is fixed in version 0.6.0.

## Affected products

- uutils coreutils uu_ln < 0.6.0

## Identifiers

- CVE-2026-35373
- GHSA-jcjr-rh8q-7xqf

## Timeline

- 2026-01-01: disclosed: Reported in Zellic uutils coreutils Program Security Assessment
- 2026-03-18: other: Pull request 11403 opened to fix the issue
- 2026-05-30: patched: Version 0.6.0 released with fix
- 2026-07-06: advisory: GitHub Advisory published

## References

- [https://github.com/uutils/coreutils/security/advisories/GHSA-jcjr-rh8q-7xqf](https://github.com/uutils/coreutils/security/advisories/GHSA-jcjr-rh8q-7xqf)
- [https://github.com/uutils/coreutils/pull/11403](https://github.com/uutils/coreutils/pull/11403)
- [https://api.github.com/repos/uutils/coreutils/security-advisories/GHSA-jcjr-rh8q-7xqf](https://api.github.com/repos/uutils/coreutils/security-advisories/GHSA-jcjr-rh8q-7xqf)

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