{"id":"CVE-2026-44897","state":"PUBLISHED","title":"Mistune Heading ID Attribute Injection XSS","description":"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 — 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.","publishedAt":"2026-05-26T20:40:42.290Z","updatedAt":"2026-06-01T17:09:12.432Z","severity":{"score":6.1,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["lepture mistune"],"affected":[{"vendor":"lepture","product":"mistune","versions":[{"version":"< 3.2.1","status":"affected"}]}],"references":["https://github.com/lepture/mistune/security/advisories/GHSA-v87v-83h2-53w7","https://github.com/lepture/mistune/releases/tag/v3.2.1"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/44xxx/CVE-2026-44897.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-44897","state":"PUBLISHED","datePublished":"2026-05-26T20:40:42.290Z","dateUpdated":"2026-06-01T17:09:12.432Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-07T21:50:33.546Z"},"containers":{"cna":{"title":"Mistune Heading ID Attribute Injection XSS","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 — 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."}],"affected":[{"vendor":"lepture","product":"mistune","versions":[{"version":"< 3.2.1","status":"affected"}]}],"references":[{"url":"https://github.com/lepture/mistune/security/advisories/GHSA-v87v-83h2-53w7","name":"https://github.com/lepture/mistune/security/advisories/GHSA-v87v-83h2-53w7","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/lepture/mistune/releases/tag/v3.2.1","name":"https://github.com/lepture/mistune/releases/tag/v3.2.1","tags":["x_refsource_MISC"]}],"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-05-26T20:40:42.290Z"},"source":{"advisory":"GHSA-v87v-83h2-53w7","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-01T17:04:08.778886Z","id":"CVE-2026-44897","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-01T17:09:12.432Z"}}]}}}