Vulnerability · Published Oct 19, 2026 · Assigned by GitHub_M

CVE-2026-111059Mercury: Stored / DOM Cross-Site Scripting (XSS): mr.Markdown renders untrusted content as raw, unsanitized HTML

Medium 6.1

In plain English

A medium-severity cross-site scripting in mercury from mljar. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.1Medium

Exploit odds (30 days)0.3%top 79.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	mercury	3.2.11	GHSA-2658-85cv-9wwq

Affected products (as reported)

Vendor	Product	Versions
mljar	mercury	>= 3.0.0, < 3.2.11

Weakness: CWE-79, CWE-116 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

https://github.com/mljar/mercury/security/advisories/GHSA-2658-85cv-9wwq x_refsource_CONFIRM
https://github.com/mljar/mercury/commit/c798a85924e6614c6fea7afe5a560e4554a1d09b x_refsource_MISC
https://github.com/mljar/mercury/releases/tag/v3.2.11 x_refsource_MISC