CVE-2026-59923

mediumCVSS 6.1covered by 1 sourcefirst seen 2026-07-08

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.

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Exploitation outlook

Low exploitation risk0.20% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 10% of all EPSS-scored CVEs.

Advisory coverage (1)

mediumCVE-2026-59923: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, HTMLRenderer.s…nvd · 2026-07-08

External references

NVD record for CVE-2026-59923

CVE.org record

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