https://db.gcve.eu Contains only the most 10 recent entries. http://www.rssboard.org/rss-specification python-feedgen en Wed, 21 Oct 2026 02:35:53 +0000 https://db.gcve.eu/vuln/fkie_cve-2026-111059 <p>Mercury is a Python framework for sharing Jupyter notebooks as web applications and dashboards. From 3.0.0 until 3.2.11, mr.Markdown converts attacker-controlled Markdown to HTML without sanitizing raw HTML before assigning it to an ipywidgets.HTML sink. Event-handler attributes and other active HTML can therefore reach the DOM and execute when another user views the application. This issue is fixed in version 3.2.11.</p> <p>Mercury is a Python framework for sharing Jupyter notebooks as web applications and dashboards. From 3.0.0 until 3.2.11, mr.Markdown converts attacker-controlled Markdown to HTML without sanitizing raw HTML before assigning it to an ipywidgets.HTML sink. Event-handler attributes and other active HTML can therefore reach the DOM and execute when another user views the application. This issue is fixed in version 3.2.11.</p> https://db.gcve.eu/vuln/fkie_cve-2026-111059 https://db.gcve.eu/vuln/ghsa-2658-85cv-9wwq <p><strong>Affected:</strong> PyPI: mercury</p> <p>## Summary</p> <p>Mercury turns Jupyter notebooks into shared web apps/dashboards. The `mr.Markdown` widget converts its input to HTML with **python-markdown and no sanitization step**. `MarkdownWidget` is an `ipywidgets.HTML` widget, whose value is written to the page as **raw HTML (via `innerHTML`) with no sanitization**, so the result reaches the DOM verbatim. When an app passes **untrusted data** (database rows, user submissions, uploaded file contents, or an external/LLM API response) to `mr.Markdown`, HTML/JS in that data executes in the browser of **whoever views the app** — a data-driven stored/DOM-based XSS.</p> <p>This is a library-provided rendering sink that fails to neutralize output; it is triggered by ordinary, reasonable application code, not by an author mistake.</p> <p>## Root cause</p> <p>`mercury/md.py` — `MarkdownWidget._to_html()` (verified at v3.2.6, lines ~57–65):</p> <p>```python def _to_html(self, text: str) -&gt; str: if md_lib is not None: body = md_lib.markdown(text) # python-markdown: passes raw HTML through else: body = f&#34;&lt;pre&gt;{escape(text)}&lt;/pre&gt;&#34; # escape() is ONLY the md-lib-absent fallback return self._apply_inline_theme(body) # regex styling — adds style=, removes nothing ```</p> <p>Two neutralization failures compound:</p> <p>1. **Markdown → HTML is unsanitized.** `python-markdown` passes raw HTML through by default: `&lt;img src=x onerror=…&gt;`, `&lt;svg onload=…&gt;`, and `javascript:` links survive verbatim. There is no `bleach`/`nh3` allowli…</p> <p><strong>Affected:</strong> PyPI: mercury</p> <p>## Summary</p> <p>Mercury turns Jupyter notebooks into shared web apps/dashboards. The `mr.Markdown` widget converts its input to HTML with **python-markdown and no sanitization step**. `MarkdownWidget` is an `ipywidgets.HTML` widget, whose value is written to the page as **raw HTML (via `innerHTML`) with no sanitization**, so the result reaches the DOM verbatim. When an app passes **untrusted data** (database rows, user submissions, uploaded file contents, or an external/LLM API response) to `mr.Markdown`, HTML/JS in that data executes in the browser of **whoever views the app** — a data-driven stored/DOM-based XSS.</p> <p>This is a library-provided rendering sink that fails to neutralize output; it is triggered by ordinary, reasonable application code, not by an author mistake.</p> <p>## Root cause</p> <p>`mercury/md.py` — `MarkdownWidget._to_html()` (verified at v3.2.6, lines ~57–65):</p> <p>```python def _to_html(self, text: str) -&gt; str: if md_lib is not None: body = md_lib.markdown(text) # python-markdown: passes raw HTML through else: body = f&#34;&lt;pre&gt;{escape(text)}&lt;/pre&gt;&#34; # escape() is ONLY the md-lib-absent fallback return self._apply_inline_theme(body) # regex styling — adds style=, removes nothing ```</p> <p>Two neutralization failures compound:</p> <p>1. **Markdown → HTML is unsanitized.** `python-markdown` passes raw HTML through by default: `&lt;img src=x onerror=…&gt;`, `&lt;svg onload=…&gt;`, and `javascript:` links survive verbatim. There is no `bleach`/`nh3` allowli…</p> https://db.gcve.eu/vuln/ghsa-2658-85cv-9wwq