CVE-2026-59923
Mistune: XSS via percent-encoded javascript URI bypass in safe_url()
CVSS Score
6.1
EPSS Score
0.0%
EPSS Percentile
0th
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, HTMLRenderer.safe_url() does not block percent-encoded javascript URIs, allowing attacker-supplied Markdown links or images to bypass URL protections and execute script in rendered HTML. This issue is fixed in version 3.3.0.
| CWE | CWE-79 |
| Vendor | lepture |
| Product | mistune |
| Published | Jul 8, 2026 |
| Last Updated | Jul 8, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
lepture / mistune
< 3.3.0