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CVE-2026-59923

MEDIUM Exploitation: PoC
6.1
CVSS 3.1
Description
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.

Metadata

CVE ID
CVE-2026-59923
State
PUBLISHED
Assigner
GitHub_M
Reserved
2026-07-07 18:20 UTC
Published
2026-07-08 16:14 UTC
Last updated
2026-07-08 16:41 UTC
Primary CWE
CWE-79
CWE-79: Improper Neutralization of Input During Web Page Gen…
Vendor / Product
lepture / mistune
Sources
cve.org  ·  NVD

Severity & Metrics

6.1 MEDIUM CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
SSVC — CISA Coordinator
Exploitation
PoC
Automatable
no
Tech. Impact
partial
Affected products (1)
VendorProductPlatformVersions
lepture mistune — < 3.3.0
Weakness (CWE)
CWESourceDescription
CWE-79 cna CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSS scores (1)
ScoreSeverityVersionSourceVector
6.1 MEDIUM 3.1 cna CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
References (3)
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