CVE-2026-66064: Github.com/patrickhener/goshs/v2 Path Traversal Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-964w-f6gj-5236",
  "modified" : "2026-07-28T22:26:28Z",
  "published" : "2026-07-28T22:26:28Z",
  "aliases" : [ "CVE-2026-66064" ],
  "summary" : "goshs has ACL Bypass & Path Traversal",
  "details" : "## Summary\n\n`sendFile` derives the served filename from the raw request path while opening the file from the cleaned path, so appending a trailing slash empties the derived name and defeats both the never-serve rule for the ACL file and the block list. \n\n## Finding (Medium): trailing-slash ACL and hidden-file bypass\n\nhttpserver/handler.go, sendFile (lines 789-801) takes the filename from the RAW req.URL.Path while the file itself is opened from the filepath.Clean-ed path. The two disagree, and a trailing slash makes the derived name the empty string. Both protections key on that derived name, so both are defeated: the rule that never serves the .goshs ACL file, and the acl.Block list.\n\nMeasured, with negative controls:\n\n```\nGET /blocked/secret.txt    -> 404          (control, correctly blocked)\nGET /blocked/secret.txt/   -> 200 + contents\nGET /blocked/.goshs/       -> 200, returns the ACL file itself,\n                              including the admin:$2a$... bcrypt hash\n```\n\nUnauthenticated when the ACL is configured block-only (common usage). Stated precisely: AUTHENTICATION IS NOT BYPASSED. An unauthenticated request against a directory protected by authentication still returns 401 under the same trick; I tested that. The claim is specifically that the block list and the ACL-file protection are bypassed. In-tree evidence that sendFile is the defect: the sibling handlers doDir and bulkDownload both derive the name correctly; sendFile is the lone outlier.\n\n## Suggested fixes\n\n1. Derive the served filename from the same cleaned path used to open the file, so the authorization decision and the file access cannot disagree.\n\n## Tooling\n\nAI assistance was used while investigating. The finding was reproduced against a running server on loopback with negative controls, including the 404-versus-200 pair and the authenticated-directory control that shows authentication is not affected.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/patrickhener/goshs/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.1.5-0.20260727065949-f3ef599e4091"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.1.4"
    }
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "goshs.de/goshs/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.1.5-0.20260727065949-f3ef599e4091"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.1.4"
    }
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/patrickhener/goshs"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.1.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "goshs.de/goshs"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.1.4"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/goshs-labs/goshs/security/advisories/GHSA-964w-f6gj-5236"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/goshs-labs/goshs/pull/222"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/goshs-labs/goshs/commit/f3ef599e409151d1380866e47de8b1afb0bb54fa"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/goshs-labs/goshs"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22", "CWE-41", "CWE-863" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-28T22:26:28Z",
    "nvd_published_at" : null
  }
}