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A critical vulnerability has been identified in the nbconvert tool, specifically affecting Jupyter environments on Windows. When converting a notebook containing SVG output to PDF using jupyter nbconvert --to pdf, the tool may inadvertently execute a malicious inkscape.bat file if present in the working directory, leading to unauthorized code execution. This flaw, tracked as CVE-2025-53000, impacts all versions up to and including 7.16.6, and currently, no official patch is available. The vulnerability is not remotely exploitable but poses a significant risk if an attacker can place a crafted batch file in a directory where a user performs notebook exports.
Security researchers have highlighted the broader risks associated with Jupyter notebook export functionality, emphasizing how threat actors could exploit external notebooks to compromise user workstations. The research underscores the importance of securing Jupyter environments, recommending the use of centralized servers, regular updates, and strict controls over external files processed by Jupyter software. The attack vector leverages the fact that configuration files in Jupyter are valid Python executables, making them particularly susceptible to exploitation if not properly managed.
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2 events from the most recent confirmed update back to the earliest known activity.
By mid-December 2025, the nbconvert uncontrolled search path vulnerability had been assigned CVE-2025-53000 and publicly described as affecting Windows systems up to and including version 7.16.6. Public reporting stated that no fix was yet available and advised users to avoid vulnerable PDF conversions or harden their environments.
The vulnerability later assigned CVE-2025-53000 was disclosed to the Jupyter team in June 2025. The issue affects nbconvert on Windows by allowing arbitrary code execution during notebook-to-PDF export when a malicious Inkscape script is present in the working directory.
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Jupyter Server disclosed and fixed a **stored cross-site scripting** flaw in `NbconvertFileHandler` and `NbconvertPostHandler` that affects versions up to and including `2.19.0`. The issue stems from nbconvert endpoints rendering user-authored notebook HTML under the Jupyter origin without a `sandbox` directive in the `Content-Security-Policy`, while `nbconvert.HTMLExporter` does not sanitize HTML by default. An attacker can place malicious HTML in notebook `display_data` output and trigger script execution when an authenticated user opens `/nbconvert/html/<path>`. Successful exploitation could expose tokens and cookies, grant access to Jupyter ` /api/* ` endpoints, and potentially enable remote code execution through kernels. The project addressed the issue in **jupyter-server `2.20.0`** by adding `sandbox allow-scripts` to the CSP header for rendered nbconvert HTML in both GET and POST handlers, isolating any JavaScript in a unique origin. The mitigation is enabled by default through the new `ServerApp.nbconvert_csp_sandbox` setting, and the change is documented and covered by tests; a configuration-based workaround is also available for deployments that cannot easily patch source files.
Jun 29, 2026
JupyterLab is affected by high-severity vulnerabilities that can lead to arbitrary code execution, security restriction bypass, and information disclosure, prompting an alert from Italy's national cybersecurity agency. The most detailed issue disclosed is **`CVE-2026-73417`**, a cross-site scripting flaw caused by improper validation of notebook margin override settings before they are inserted into style content. An attacker can exploit `CVE-2026-73417` by persuading a user to import a malicious `overrides.json` settings file or by placing that file in a shared settings location so it is applied automatically. Successful exploitation allows code to run with the victim's privileges, enabling reading or modifying notebooks and files and executing code through the notebook server, including on a connected kernel. The flaw affects JupyterLab versions `3.3.0` through `4.5.9` and `4.6.0` through `4.6.1`; fixes are available in **`4.5.10`** and **`4.6.2`**, and organizations are advised to update vulnerable installations in line with vendor guidance.
Aug 14, 2026
Microsoft released a security update for **Windows Notepad** to fix `CVE-2026-20841`, a high-severity remote code execution vulnerability tracked in the Microsoft Security Update Guide. The flaw affects Notepad's handling of specially crafted **Markdown** documents and stems from improper neutralization of special elements, allowing arbitrary code execution under certain conditions. Successful exploitation requires user interaction: a victim must open a malicious Markdown file in Notepad and click a URL embedded in the document. CSIRT.SK reported the issue carries a **CVSS 8.8** rating and that a public proof-of-concept exploit is available, increasing the urgency for organizations to deploy the patch and update Windows Notepad across affected systems.
Jul 24, 2026