CVE-2026-59923
MEDIUMMistune: XSS via percent-encoded javascript URI bypass in safe_url()
Title source: cnaDescription
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.
References (3)
Core 3
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/lepture/mistune/security/advisories/GHSA-8c25-4j27-2rv3
X_Refsource_Misc x_refsource_misc
https://github.com/lepture/mistune/commit/c7101fcbb6e8790e8e39157c5ca2238fc6dd6cbc
X_Refsource_Misc x_refsource_misc
https://github.com/lepture/mistune/releases/tag/v3.3.0
Scores
CVSS v3
6.1
EPSS
0.0024
EPSS Percentile
14.9%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
partial
Details
CWE
CWE-79
Status
published
Products (3)
lepture/mistune
< 3.3.0
mistune_project/mistune
< 3.3.0
pypi/mistune
0 - 3.3.0PyPI
Published
Jul 08, 2026
Tracked Since
Jul 08, 2026