# CVE-2026-61801: github.com/moby/sys/user has a possible DoS via unbounded parsing of user and group database files

CVE-2026-61801 is fixed in 10 products on 1 platform, first by DEBIAN-CVE-2026-61801, released October 10, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-61801
- Priority: Routine
- CVSS: 5.5 (Moderate)
- EPSS: 0.0012
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 8, 2026
- Weakness: Uncontrolled Resource Consumption
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-61801

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | containerd amzn 2023 | 2.3.7-1.amzn2023.0.1 | [ALAS2023-2026-3273](https://patchblox.com/security/data/fix/linux/alas2023-2026-3273.md) | Nov 7, 2026 |
| Linux | containerd-debuginfo amzn 2023 | 2.3.7-1.amzn2023.0.1 | [ALAS2023-2026-3273](https://patchblox.com/security/data/fix/linux/alas2023-2026-3273.md) | Nov 7, 2026 |
| Linux | containerd-debugsource amzn 2023 | 2.3.7-1.amzn2023.0.1 | [ALAS2023-2026-3273](https://patchblox.com/security/data/fix/linux/alas2023-2026-3273.md) | Nov 7, 2026 |
| Linux | containerd-stress amzn 2023 | 2.3.7-1.amzn2023.0.1 | [ALAS2023-2026-3273](https://patchblox.com/security/data/fix/linux/alas2023-2026-3273.md) | Nov 7, 2026 |
| Linux | containerd-stress-debuginfo amzn 2023 | 2.3.7-1.amzn2023.0.1 | [ALAS2023-2026-3273](https://patchblox.com/security/data/fix/linux/alas2023-2026-3273.md) | Nov 7, 2026 |
| Linux | golang-github-moby-sys Debian 14 | 0.0~git20260904.79376e0-1 | [DEBIAN-CVE-2026-61801](https://patchblox.com/security/data/fix/linux/debian-cve-2026-61801.md) | Oct 10, 2026 |
| Linux | runc amzn 2023 | 1.4.3-1.amzn2023.0.3 | [ALAS2023-2026-3323](https://patchblox.com/security/data/fix/linux/alas2023-2026-3323.md) | Nov 7, 2026 |
| Linux | runc-debuginfo amzn 2023 | 1.4.3-1.amzn2023.0.3 | [ALAS2023-2026-3323](https://patchblox.com/security/data/fix/linux/alas2023-2026-3323.md) | Nov 7, 2026 |
| Linux | runc-debugsource amzn 2023 | 1.4.3-1.amzn2023.0.3 | [ALAS2023-2026-3323](https://patchblox.com/security/data/fix/linux/alas2023-2026-3323.md) | Nov 7, 2026 |
| Linux | soci-snapshotter amzn 2023 | 0.16.1-1.amzn2023.0.1 | [ALAS2023-2026-3351](https://patchblox.com/security/data/fix/linux/alas2023-2026-3351.md) | Nov 7, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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