---
id: CVE-2026-35347
aliases:
  - GHSA-3wfc-mgpm-9rq6
title: 'comm: FIFO/pipe inputs are drained before comparison (data loss / hang)'
summary: 'comm: FIFO/pipe inputs are drained before comparison (data loss / hang)'
severity: medium
cvss: 4.4
cwe:
  - CWE-20
vendor: uu_comm
product: uu_comm
ecosystem: rust
affected:
  - uu_comm < 0.6.0
patched:
  - uu_comm 0.6.0
published: '2026-07-06'
updated: '2026-07-06'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-3wfc-mgpm-9rq6'
references:
  - url: >-
      https://github.com/uutils/coreutils/security/advisories/GHSA-3wfc-mgpm-9rq6
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-35347'
  - url: 'https://github.com/uutils/coreutils/pull/9545'
  - url: >-
      https://github.com/uutils/coreutils/commit/75f45e87e52ed95840494963ab9a28651165d56e
  - url: 'https://github.com/uutils/coreutils/releases/tag/0.6.0'
  - url: 'https://github.com/advisories/GHSA-3wfc-mgpm-9rq6'
tags:
  - ghsa
  - rust
epss: 0.00135
epssPercentile: 0.03315
ingestedAt: '2026-07-06T20:46:12.673Z'
---

## Overview

The comm utility in uutils coreutils incorrectly consumes data from non-regular file inputs before performing comparison operations. The are_files_identical function opens and reads from both input paths to compare content without first verifying if the paths refer to regular files. If an input path is a FIFO or a pipe, this pre-read operation drains the stream, leading to silent data loss before the actual comparison logic is executed. Additionally, the utility may hang indefinitely if it attempts to pre-read from infinite streams like /dev/zero.

---
_Zellic finding 3.35. Reported in the Zellic *uutils coreutils Program Security Assessment* (for Canonical, Jan 2026), audited commit `3a07ffc5a9bd4c283e75afa548ba1f1957bad242`._

## Affected packages

- `uu_comm < 0.6.0`

## Remediation

Upgrade to a patched release:

- `uu_comm 0.6.0`