Vulnerability in Lepture Mistune

CVE-2026-59922

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a run of closed tilde, equals-sign, or caret marker pairs around a character causes quadratic work in src/mistune/plugins/formatting.py when the strikethrough…

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-59922?
CVE-2026-59922 is a high-severity vulnerability in Lepture Mistune, classified under Inefficient Algorithmic Complexity. CVSS score: 7.5/10. Published 2026-07-08.
How severe is CVE-2026-59922?
High severity. CVSS v3 base score is 7.5 out of 10.