{"id":"CVE-2026-44898","title":"Mistune TOC Anchor Injection XSS","published":"2026-05-26T17:16:39.810Z","updated":"2026-07-24T07:10:00.170Z","severity":"medium","cvssScore":6.1,"epss":0.00228,"epssPct":0.13706,"kev":false,"maturity":"none","actionScore":24,"primaryVendor":"mistune project","primaryProduct":"mistune","cweId":"CWE-79","fixAvailable":true,"tags":["pre-auth","xss","remote"],"epssDelta7":0,"summary":"Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, render_toc_ul() builds a <ul> table-of-contents tree from a list of (level, id, text) tuples. Both the id value (used as href=\"#<id>\") and the text value (used as the visible link label) are inserted into <a> tags via a plain Python format string — with no HTML escaping applied to either value. When heading IDs are derived from user-supplied heading text (the standard use-case for readable slug anchors), an attacker can craft a heading whose text breaks out of the href=\"#...\" attribute context, injecting arbitrary HTML tags including <script> blocks directly into the rendered TOC. This vulnerability is fixed in 3.2.1.","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","cvssVersion":"3.1","cvssSource":"nvd-secondary","cweName":"Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","kevAdded":null,"kevDue":null,"kevRansomware":null,"source":"nvd","cna":"GitHub_M","ssvc":{"exploitation":"poc","automatable":"no","impact":"partial"},"sources":{"adp":"2026-05-27T17:57:38.643Z","cna":"2026-05-27T17:57:38.643Z","osv":"2026-11-13T03:18:18.039Z","epss":"2026-11-12","cna_seen":"2026-09-29T11:21:50.240Z"},"cvssCna":{"score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","version":"3.1"},"hasPatchRef":false,"credits":[],"counts":{"exploitdb":0,"metasploit":0,"nuclei":0,"githubPoc":0},"products":[{"vendor":"mistune project","product":"mistune","cpe":"cpe:2.3:a:mistune_project:mistune"}],"references":[{"url":"https://github.com/lepture/mistune/releases/tag/v3.2.1","tags":"Product,Release Notes"}],"exploits":[],"analysis":null,"affectedVersions":[{"vendor":"mistune project","product":"mistune","version":"*","vsi":null,"vse":null,"vei":null,"vee":"3.2.1"}],"source_attribution":"NVD (NIST), CVE Program, CISA KEV, FIRST EPSS, OSV. Aggregated by Noroxi."}