CVE-2026-111059

Mercury: Stored / DOM Cross-Site Scripting (XSS): mr.Markdown renders untrusted content as raw, unsanitized HTML

State: Published
Severity: 6.1 Medium
Published: Oct 19, 2026
Updated: Oct 20, 2026
Reserved: Oct 15, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	6.1 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	GitHub_M

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-116 Improper Encoding or Escaping of Output

Affected Products

Product	Versions
mercurymljar	>= 3.0.0, < 3.2.11Affected

References

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