CVE-2026-59927: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the Include directive in src/mistune/directives/include.py detects only direct self-includes and not

mediumCVSS 5.3CVE-2026-59927

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the Include directive in src/mistune/directives/include.py detects only direct self-includes and not indirect cycles, allowing two markdown files that include each other to trigger unbounded recursion, raise RecursionError, and crash the rendering request. This issue is fixed in version 3.3.0.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: medium — CVSS 5.3
Published: 2026-07-08
Last updated: 2026-07-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-59927

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-599270.31% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 23% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-59927	coverage & exploitation status	NVD · CVE.org

Recent advisories for Mistune is a

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highGHSA-qcq2-496w-v96p: Mistune: Potential DoS via quadratic-time parsing in parse_link_textghsa · 2026-07-09
mediumCVE-2026-59930: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the toc plugin…nvd · 2026-07-08
mediumCVE-2026-59929: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the safe_url f…nvd · 2026-07-08
highCVE-2026-59928: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a Markdown doc…nvd · 2026-07-08
mediumCVE-2026-59926: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, render_admonit…nvd · 2026-07-08
highCVE-2026-59925: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, long sequences…nvd · 2026-07-08

CVE-2026-59927: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the Include directive in src/mistune/directives/include.py detects only direct self-includes and not

Details

Exploitation outlook

Referenced CVEs

Recent advisories for Mistune is a

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