CVE-2026-111058
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk37th percentile - higher than 37% of all known CVEs
Summary
Mercury is a Python framework for sharing Jupyter notebooks as web applications and dashboards. Prior to 3.2.6, default tokenless deployments allow anonymous clients to create Jupyter kernels and send execute_request messages containing arbitrary Python. The endpoint blocklist does not cover /api/kernels, and the websocket wrapper previously tracked idle activity without authorizing executable messages.
Risk Assessment
An anonymous attacker can execute arbitrary Python code in the context of the Mercury process, leading to server compromise and data access. The risk is high for publicly exposed deployments.
Recommendation
Update Mercury to version 3.2.6 or later. Until patched, do not expose tokenless deployments on untrusted networks and restrict access to /api/kernels endpoints.
Other vulnerabilities in Mercury
See all- CVE-2026-111057Critical
Mercury is a Python framework for sharing Jupyter notebooks as web applications and dashboards. From 3.0.0 until 3.2.4, a missing comma in BLOCKED_PATTERNS concatenates the /lab and /api/terminals regular-expression literals. Requests to /api/terminals therefore bypass the anonymous endpoint blocklist and reach Jupyter Server's terminal API. An unauthenticated attacker can use the resulting interactive operating-system shell to execute commands and access data available to the Mercury process.
- CVE-2026-111059Medium
In Mercury 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 reach the DOM and execute when another user views the application.
Original NVD description (English source)
Mercury is a Python framework for sharing Jupyter notebooks as web applications and dashboards. Prior to 3.2.6, default tokenless deployments allow anonymous clients to create Jupyter kernels and send execute_request messages containing arbitrary Python. The endpoint blocklist does not cover /api/kernels, and the websocket wrapper previously tracked idle activity without authorizing executable messages. This issue is fixed in version 3.2.6.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS