Live › vulnerability › CVE-2026-115351
Go to dashboardMistune, a Python Markdown parser, does not validate the figwidth option of its figure directive, so attacker-controlled markdown can add arbitrary CSS declarations to rendered output. An attacker can use this to make victim browsers request URLs on attacker servers and leak attribute values.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Applications that render untrusted or user-supplied markdown with mistune 3.2.1 through 3.2.x and use the figure directive, since the injected style lands in the rendered HTML. Sites that only render trusted markdown, or that do not use the figure directive, are unlikely to be exposed.
No product ranges from the sources yet.
pip show mistune and check whether the version is at least 3.2.1 and below 3.3.0figure directives or figwidth usage in rendered markdown3.3.0 or laterEach row is the first time that source carried this signal. The analyst’s rows are its own findings.
Mistune from 3.2.1 before 3.3.0 contains a CSS injection vulnerability that allows attackers controlling markdown input to inject arbitrary style declarations via the unvalidated figwidth option of the figure directive. Attackers can append declarations like background:url() to the rendered figure style attribute, forcing victim browsers to send requests to attacker servers and leak attribute values.
This page as .md · .json · in your agent: get_signal("CVE-2026-115351")
NVD data is provided by NIST and is public domain · EPSS scores by FIRST, used with attribution. Posts quoted belong to their authors.