{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-44897", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-05-07T21:50:33.546Z", "datePublished": "2026-05-26T20:40:42.290Z", "dateUpdated": "2026-05-26T20:40:42.290Z"}, "containers": {"cna": {"title": "Mistune Heading ID Attribute Injection XSS", "problemTypes": [{"descriptions": [{"cweId": "CWE-79", "lang": "en", "description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.1, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "version": "3.1"}}], "references": [{"name": "https://github.com/lepture/mistune/security/advisories/GHSA-v87v-83h2-53w7", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/lepture/mistune/security/advisories/GHSA-v87v-83h2-53w7"}, {"name": "https://github.com/lepture/mistune/releases/tag/v3.2.1", "tags": ["x_refsource_MISC"], "url": "https://github.com/lepture/mistune/releases/tag/v3.2.1"}], "affected": [{"vendor": "lepture", "product": "mistune", "versions": [{"version": "< 3.2.1", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-05-26T20:40:42.290Z"}, "descriptions": [{"lang": "en", "value": "Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening <hN> tag by string-concatenating the id attribute value directly into the HTML \u2014 with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character \" in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element. This vulnerability is fixed in 3.2.1."}], "source": {"advisory": "GHSA-v87v-83h2-53w7", "discovery": "UNKNOWN"}}}}

{}

{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*", "matchCriteriaId": "A91629D7-7A30-4A3F-B1AD-17FE21D59820", "versionEndExcluding": "3.2.1", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening <hN> tag by string-concatenating the id attribute value directly into the HTML \u2014 with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character \" in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element. This vulnerability is fixed in 3.2.1."}], "id": "CVE-2026-44897", "lastModified": "2026-05-28T13:42:42.863", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.1, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 2.7, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-05-26T21:16:39.657", "references": [{"source": "security-advisories@github.com", "tags": ["Product", "Release Notes"], "url": "https://github.com/lepture/mistune/releases/tag/v3.2.1"}, {"source": "security-advisories@github.com", "tags": ["Exploit", "Vendor Advisory"], "url": "https://github.com/lepture/mistune/security/advisories/GHSA-v87v-83h2-53w7"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-79"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,3.2.1)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "mistune", "source": "cna", "vendor": "lepture"}, "product": "mistune", "vendor": "lepture"}], "created": "2026-05-26T22:45:06.253691+00:00", "updated": "2026-05-26T23:00:17.027930+00:00", "vendors": ["lepture", "lepture$PRODUCT$mistune"]}