github.com/moby/sys/user has a possible DoS via unbounded parsing of user and group database files

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

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.

Source published

8 Oct 2026 16:22:25 UTC

Source modified

8 Oct 2026 17:27:37 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

Source published

Oct 8, 2026, 4:22:25 PM (timezone not stated)

Source modified

Oct 8, 2026, 5:27:37 PM (timezone not stated)

Observed here

7 Nov 2026 13:27:15 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

Source published

8 Oct 2026 17:17:17 UTC

Source modified

8 Oct 2026 21:35:53 UTC

Observed here

25 Oct 2026 14:19:28 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

A denial-of-service (DoS) vulnerability exists in `github.com/moby/sys/user` before v0.4.1 when parsing specially crafted user or group database files. An attacker able to supply a malicious `/etc/passwd` or `/etc/group`-style file may cause excessive memory consumption, potentially resulting in process termination due to Out Of Memory (OOM) conditions. This issue is related to containerd [CVE-2026-47262] / [GHSA-jpcc-p29g-p8mq](https://github.com/containerd/containerd/security/advisories/GHSA-jpcc-p29g-p8mq), which describes one practical exploitation path through processing untrusted container image content. Applications using `github.com/moby/sys/user` to parse untrusted user or group database files may be similarly affected. ### Impact `github.com/moby/sys/user` versions before v0.4.1 do not place sufficient limits on entries while parsing user and group database files. A specially crafted file may cause excessive memory consumption, potentially leading to process termination due to Out Of Memory (OOM) conditions. Applications that use `github.com/moby/sys/user` to parse user-supplied or otherwise untrusted `/etc/passwd` or `/etc/group` files may be affected. The severity depends on whether an attacker can influence the contents of files being parsed. ### Patches This issue is fixed in `github.com/moby/sys/user` v0.4.1. Users should upgrade to v0.4.1 or later. ### Workarounds Avoid parsing attacker-controlled `/etc/passwd` or `/etc/group`-style files with affected versions of `github.com/moby/sys/user`. Applications that must process untrusted user or group database files should validate and limit accepted input before parsing. Upgrading to v0.4.1 or later is the recommended remediation. ### References * containerd CVE-2026-47262 / GHSA-jpcc-p29g-p8mq: https://github.com/containerd/containerd/security/advisories/GHSA-jpcc-p29g-p8mq * Fix in `github.com/moby/sys/user`: https://github.com/moby/sys/user/commit/210d32ba2bcb4544ee968c7f31249fe59796e60b

Source published

8 Oct 2026 16:08:33 UTC

Source modified

19 Oct 2026 21:40:47 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Publisher rating · MODERATE

Possible DoS via unbounded parsing of user and group database files in github.com/moby/sys/user

Source published

19 Oct 2026 21:08:21 UTC

Source modified

19 Oct 2026 21:31:35 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.