{"cve":"CVE-2026-44898","nvd":{"published":"2026-05-26T21:16:39.810","modified":"2026-07-24T11:10:00.170","status":"Analyzed","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["https://github.com/lepture/mistune/releases/tag/v3.2.1","https://github.com/lepture/mistune/security/advisories/GHSA-6269-cqxg-mhhv","https://github.com/lepture/mistune/security/advisories/GHSA-6269-cqxg-mhhv"],"products":["mistune_project:mistune"],"source":"nvd","synced_at":"2026-10-19T22:36:28.938604137+00:00"},"epss":{"cve":"CVE-2026-44898","score":0.00228,"percentile":0.13623,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-6269-cqxg-mhhv","url":"https://osv.dev/vulnerability/GHSA-6269-cqxg-mhhv","summary":"Mistune TOC Anchor Injection XSS","modified":"2026-07-13T07:26:41.251640966Z","packages":[{"ecosystem":"PyPI","name":"mistune","purl":"pkg:pypi/mistune","ranges":[">=3.2.0 <3.2.1"],"fixed":["3.2.1"]}]},{"id":"PYSEC-2026-2208","url":"https://osv.dev/vulnerability/PYSEC-2026-2208","summary":"","modified":"2026-07-13T07:15:28.986856174Z","packages":[{"ecosystem":"PyPI","name":"mistune","purl":"pkg:pypi/mistune","ranges":["<3.2.1"],"fixed":["3.2.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}