CVE-2026-44899
Fixed upstream EPSS <1%CVSS 4.7
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, the Image directive plugin validates the :width: and :height: options with a regex compiled as _num_re = re.compile(r"^\d+(?:\.\d*)?"). When the validated value is not a plain integer, render_block_image() inserts it directly into a style="width:...;" or style="height:...;" attribute. Because the value was accepted by the prefix-only regex, any CSS after the leading digits reaches the style= attribute verbatim and without escaping. This vulnerability is fixed in 3.2.1.
Products: lepture mistune
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| PyPI | mistune | 3.2.1 |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Debian 12 | mistune | no fix |
| Debian 13 | mistune | no fix |
| Debian 14 | mistune | no fix |
| Ubuntu 16.04 LTS | mistune | no fix |
| Ubuntu 18.04 LTS | mistune | no fix |
| Ubuntu 20.04 LTS | mistune | no fix |
| Ubuntu 22.04 LTS | mistune | no fix |
| Ubuntu 22.04 LTS | mistune0 | no fix |
| Ubuntu 24.04 LTS | mistune | no fix |
| Ubuntu 24.04 LTS | mistune0 | no fix |
| Ubuntu 25.10 | mistune | no fix |
| Ubuntu 25.10 | mistune0 | no fix |
| Ubuntu 26.04 LTS | mistune | no fix |
| Ubuntu 26.04 LTS | mistune0 | no fix |
| Ubuntu 26.10 | mistune | no fix |
| Ubuntu 26.10 | mistune0 | no fix |