PT-2026-59327 · Pypi · Nicegui

Published

2026-07-13

·

Updated

2026-07-13

CVSS v3.1

7.5

High

VectorAV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Summary

ui.restructured text() renders reStructuredText server-side with Docutils without disabling file insertion directives.
When a NiceGUI application passes attacker-controlled content to ui.restructured text(), an attacker can use standard Docutils directives (include, csv-table with :file:, raw with :file:) to read local files readable by the NiceGUI server process.
Applications that only pass trusted static strings to ui.restructured text() are not affected.

Details

The affected component is the reStructuredText renderer:
  • File: nicegui/elements/restructured text.py
  • Function: prepare content()
prepare content() renders user-supplied reStructuredText through Docutils:
python
html = publish parts(
  remove indentation(content),
  writer name='html4',
  settings overrides={'syntax highlight': 'short'},
)
The Docutils call only sets syntax highlight. It does not disable file insertion or raw directives, so Docutils processes directives that read local files and embed their contents into the generated HTML before it is returned to the browser. Frontend sanitization cannot prevent this because the file has already been read server-side.
A minimal vulnerable usage pattern is any page that forwards untrusted input into ui.restructured text(), e.g. content taken from query parameters, form fields, or other user-controlled sources.

Impact

Local file disclosure. An attacker who can supply reStructuredText content can read files accessible to the NiceGUI server process. Depending on deployment, this may expose:
  • application .env files
  • database URLs, API tokens, session/storage secrets
  • OAuth or cloud credentials
  • Docker or Kubernetes mounted secrets
  • application source files
  • logs and other process-readable files
The confirmed impact is confidentiality loss through arbitrary local file read. Applications are only impacted when they pass untrusted or user-controlled reStructuredText into ui.restructured text().

Recommended fix

Disable unsafe Docutils features in prepare content():
python
html = publish parts(
  remove indentation(content),
  writer name='html4',
  settings overrides={
    'syntax highlight': 'short',
    'file insertion enabled': False,
    'raw enabled': False,
    ' disable config': True,
  },
)
This blocks the include, csv-table :file:, and raw :file: directives as well as local docutils.conf overrides.

Fix

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Related Identifiers

PYSEC-2026-2679

Affected Products

Nicegui