CVE-2026-59930
MEDIUMDescription
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the toc plugin and TableOfContents directive generate heading IDs as predictable toc_N values without slugifying the heading text, allowing attacker-controlled id="toc_N" content to collide with generated anchors and redirect same-page navigation, CSS selectors, or JavaScript handlers. This issue is fixed in version 3.3.0.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 9% of all known CVEs.
References
Related Vulnerabilities
Other CWE-345 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-38831 | High | 7.8 | 98% | KEV + Ransom | Fix |
| CVE-2016-4553 | High | 8.6 | 80% | - | Fix |
| CVE-2016-4554 | High | 8.6 | 39% | - | Fix |
| CVE-2023-35719 | Medium | 6.8 | 26% | - | - |
| CVE-2022-26871 | Critical | 9.8 | 20% | KEV | - |
| CVE-2014-4936 | High | 9.3 | 17% | - | - |
Common questions
How do I fix CVE-2026-59930?
Upgrade mistune to 3.3.0 or later.
Is CVE-2026-59930 being actively exploited?
Not that we know of. CVE-2026-59930 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.19% is the estimated probability that it will be exploited in the next 30 days. That is higher than 9% of all scored CVEs.
How severe is CVE-2026-59930?
CVE-2026-59930 has a CVSS v3 base score of 4.3, rated moderate. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-59930 affect?
Published advisories record a fix for mistune (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-59930
Markdown
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<a href="https://tridentstack.com/cve/CVE-2026-59930"><img src="https://tridentstack.com/cve/badge/CVE-2026-59930.svg" alt="CVE-2026-59930"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-09.