CVE-2026-44898

{"id": "CVE-2026-44898", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 6.1, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 2.7, "exploitabilityScore": 2.8}]}, "published": "2026-05-26T21:16:39.810", "references": [{"url": "https://github.com/lepture/mistune/releases/tag/v3.2.1", "tags": ["Product", "Release Notes"], "source": "security-advisories@github.com"}, {"url": "https://github.com/lepture/mistune/security/advisories/GHSA-6269-cqxg-mhhv", "tags": ["Exploit", "Vendor Advisory"], "source": "security-advisories@github.com"}, {"url": "https://github.com/lepture/mistune/security/advisories/GHSA-6269-cqxg-mhhv", "tags": ["Exploit", "Vendor Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-79"}]}], "descriptions": [{"lang": "en", "value": "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 \u2014 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."}], "lastModified": "2026-05-28T13:42:13.527", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A91629D7-7A30-4A3F-B1AD-17FE21D59820", "versionEndExcluding": "3.2.1"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}