CVE-2026-59929

EUVD-2026-42336
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the safe_url filter in src/mistune/renderers/html.py blocks only javascript:, vbscript:, file:, and data: schemes, allowing legacy or chained schemes such as feed:, view-source:, jar:, livescript:, mocha:, ms-its:, mk:, and res: to reach rendered href and src attributes and potentially execute script in affected user agents. This issue is fixed in version 3.3.0.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
6.1 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 13.48%
Affected Products (NVD)
VendorProductVersion
mistune_projectmistune
𝑥
< 3.3.0
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
mistune
bookworm
postponed
bullseye
postponed
forky
vulnerable
sid
vulnerable
trixie
no-dsa
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
mistune
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
questing
ignored
resolute
needs-triage