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

{
  "id": "d2f05a1124583ffbf435b4f6642a87f09ed07c83bfe5e19212fbd089ed12cf07",
  "url": "https://osv.dev/vulnerability/GHSA-mjcv-p78q-w5fw",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "github.com/moby/sys/user has a possible DoS via unbounded parsing of user and group database files",
    "summary": "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 version",
    "evidence": "osv:GHSA-mjcv-p78q-w5fw",
    "products": [
      {
        "name": {
          "value": "github.com/moby/sys/user",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.4.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "GHSA-mjcv-p78q-w5fw",
      "aliases": [
        "CVE-2026-61801",
        "GHSA-mjcv-p78q-w5fw",
        "GO-2026-6686"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.4.1"
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              ]
            }
          ],
          "package": {
            "name": "github.com/moby/sys/user",
            "purl": "pkg:golang/github.com/moby/sys/user",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-mjcv-p78q-w5fw/GHSA-mjcv-p78q-w5fw.json",
            "last_known_affected_version_range": "<= 0.4.0"
          }
        }
      ],
      "modified": "2026-10-19T21:40:47.349593935Z",
      "provider": "osv",
      "references": [
        "https://github.com/moby/sys/security/advisories/GHSA-mjcv-p78q-w5fw",
        "https://github.com/moby/sys/pull/221",
        "https://github.com/moby/sys/commit/85a71bbe1faa36c552a960e6a5f3d0cfb632fbbe",
        "https://github.com/moby/sys"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-400"
        ],
        "severity": "MODERATE",
        "github_reviewed": true,
        "nvd_published_at": null,
        "github_reviewed_at": "2026-10-08T16:08:33Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-61801",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 376738,
  "published_at": "2026-10-08T16:08:33+00:00"
}

{
  "id": "8bdda774b20d0e6c0b5598e34e3cab5d3ac923f1e27c77efaf8cd114781c173e",
  "url": "https://osv.dev/vulnerability/GO-2026-6686",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Possible DoS via unbounded parsing of user and group database files in github.com/moby/sys/user",
    "summary": "Possible DoS via unbounded parsing of user and group database files in github.com/moby/sys/user",
    "evidence": "osv:GO-2026-6686",
    "products": [
      {
        "name": {
          "value": "github.com/moby/sys/user",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.4.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "GO-2026-6686",
      "aliases": [
        "CVE-2026-61801",
        "GHSA-mjcv-p78q-w5fw",
        "GO-2026-6686"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.4.1"
                }
              ]
            }
          ],
          "package": {
            "name": "github.com/moby/sys/user",
            "purl": "pkg:golang/github.com/moby/sys/user",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://vuln.go.dev/ID/GO-2026-6686.json"
          },
          "ecosystem_specific": {
            "imports": [
              {
                "path": "github.com/moby/sys/user",
                "symbols": [
                  "CurrentGroup",
                  "GetAdditionalGroups",
                  "GetAdditionalGroupsPath",
                  "GetExecUser",
                  "GetExecUserPath",
                  "LookupGid",
                  "LookupGroup",
                  "ParseGroup",
                  "ParseGroupFile",
                  "ParseGroupFileFilter",
                  "ParseGroupFilter"
                ]
              }
            ]
          }
        }
      ],
      "modified": "2026-10-19T21:31:35.458679290Z",
      "provider": "osv",
      "references": [
        "https://github.com/moby/sys/security/advisories/GHSA-mjcv-p78q-w5fw",
        "https://github.com/moby/sys/commit/85a71bbe1faa36c552a960e6a5f3d0cfb632fbbe",
        "https://github.com/moby/sys/pull/221"
      ],
      "provider_metadata": {
        "url": "https://pkg.go.dev/vuln/GO-2026-6686",
        "review_status": "REVIEWED"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-61801",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 376545,
  "published_at": "2026-10-19T21:08:21+00:00"
}