CVE-2026-73415 in JupyterLab
Summary
by MITRE • 08/12/2026
jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. Prior to 4.5.10 and 4.6.2, in packages/imageviewer/src/widget.ts, JupyterLab's ImageViewer uses URL.createObjectURL for a specially crafted SVG image and revokes the blob URL too early, allowing the image to retain an executable same-origin context when it is opened through the image viewer and then opened in a new browser tab. The resulting cross-site scripting can be used to execute arbitrary code on the JupyterLab server. This issue is fixed in versions 4.5.10 and 4.6.2.
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Analysis
by VulDB Data Team • 08/12/2026
The vulnerability in JupyterLab's ImageViewer component represents a critical cross-site scripting flaw that arises from improper handling of blob URLs within the image viewing functionality. This security issue exists in versions prior to 4.5.10 and 4.6.2, specifically affecting the packages/imageviewer/src/widget.ts file where URL.createObjectURL is utilized for SVG images. The core technical flaw stems from the premature revocation of blob URLs, which creates a window where malicious SVG content can maintain executable same-origin context even after the initial image display. This behavior violates fundamental web security principles and creates a dangerous scenario where user-supplied content can escape its intended sandboxed environment.
The operational impact of this vulnerability extends beyond simple XSS attacks to enable full code execution on the JupyterLab server itself. When users open malicious SVG images through the ImageViewer and subsequently open them in new browser tabs, the retained executable context allows attackers to leverage this privilege escalation to run arbitrary code with the same privileges as the JupyterLab server. This creates a significant threat vector for remote code execution attacks, particularly in environments where JupyterLab serves as a collaborative platform for data science workloads. The vulnerability is categorized under CWE-79 as Cross-Site Scripting and aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, specifically targeting browser-based command execution through malicious web content.
The security implications are particularly severe given JupyterLab's architecture as an extensible environment for interactive computing that often processes untrusted user content in collaborative settings. The flaw demonstrates poor resource management practices in URL handling where the timing of blob URL revocation creates a race condition allowing malicious content to persist beyond its intended lifecycle. Organizations using JupyterLab in production environments face elevated risk of compromise, especially when the platform handles sensitive data or operates with elevated privileges. This vulnerability is particularly concerning for cloud-based JupyterLab deployments and enterprise environments where multiple users interact with shared computational resources.
Mitigation strategies should prioritize immediate upgrade to versions 4.5.10 or 4.6.2 where the fix properly manages blob URL lifecycle, ensuring that URLs are not prematurely revoked before all potential execution contexts have completed. Organizations should also implement additional security controls such as content validation for SVG files, sandboxing measures for image rendering, and network segmentation to limit the impact of potential exploitation. The fix addresses the underlying issue by implementing proper URL lifecycle management that prevents premature blob URL revocation while maintaining the intended functionality of the ImageViewer component. Security teams should conduct thorough vulnerability assessments of their JupyterLab deployments to identify any potential exploitation attempts and establish monitoring procedures for suspicious image loading activities.