CVSS 3.1
6.1 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NCVE-2026-44897
Medium (6.1) in mistune project mistune. EPSS 0.2% chance of exploitation in the next 30 days. Fixed in mistune 3.2.1.
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening <hN> tag by string-concatenating the id attribute value directly into the HTML — with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character " in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element. This vulnerability is fixed in 3.2.1.
Severity
- EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 13% of CVEs (scores of 2026-10-31)
- CWE
- CWE-79
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mistune_project:mistune
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-v87v-83h2-53w7 | PyPI | mistune | <3.2.1 | 3.2.1 |
| PYSEC-2026-2207 | PyPI | mistune | <3.2.1 | 3.2.1 |