---
id: CVE-2026-61801
title: >-
  The `github.com/moby/sys/user` package provides Go utilities for parsing and
  looking up entries in Unix-style user and group database files
summary: >-
  The `github.com/moby/sys/user` package provides Go utilities for parsing and
  looking up entries in Unix-style user and group database files. Versions
  before 0.4.1 do not sufficiently limit entries when parsing `/etc/passwd`- or
  `/etc/gro…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
vendor: moby
product: sys
affected:
  - sys < 0.4.1
patched:
  - github.com/moby/sys/user 0.4.1
published: '2026-10-08'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:35:53.890'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-61801'
references:
  - url: >-
      https://github.com/moby/sys/commit/85a71bbe1faa36c552a960e6a5f3d0cfb632fbbe
    label: security-advisories@github.com
  - url: 'https://github.com/moby/sys/pull/221'
    label: security-advisories@github.com
  - url: 'https://github.com/moby/sys/security/advisories/GHSA-mjcv-p78q-w5fw'
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-mjcv-p78q-w5fw'
  - url: 'https://github.com/moby/sys'
tags:
  - nvd
  - cve.org
  - ghsa
  - go
  - osv
aliases:
  - GHSA-mjcv-p78q-w5fw
ecosystem: go
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-08T17:27:31.522788Z'
ingestedAt: '2026-10-08T16:52:14.783Z'
---

## Overview

The `github.com/moby/sys/user` package provides Go utilities for parsing and looking up entries in Unix-style user and group database files. Versions before 0.4.1 do not sufficiently limit entries when parsing `/etc/passwd`- or `/etc/group`-style files, allowing an attacker who can supply a specially crafted file to cause excessive memory consumption and potentially terminate the affected process due to an out-of-memory condition. This issue is patched in version 0.4.1. As a workaround, avoid parsing attacker-controlled user or group database files, or validate and limit untrusted input before parsing it.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-61801)

Affected packages:

- `github.com/moby/sys/user <= 0.4.0`

Patched in:

- `github.com/moby/sys/user 0.4.1`

Source: https://github.com/advisories/GHSA-mjcv-p78q-w5fw