Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, render_admonition() in src/mistune/directives/admonition.py concatenates the Admonition directive :class: option into the HTML class attribute without escaping, allowing attribute injection and cross-site scripting even when HTMLRenderer escape mode is enabled. This issue is fixed in version 3.2.1.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-79"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59926.json"
}{
"extracted_events": [
{
"cpe": "cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "3.3.0"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "a3cb6e5655308797e8be021d6c7b5bab13cbace2"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "v3.2.1",
"range": [
{
"fixed": "067f90861088a496942f5eb43236135352b85d39"
}
],
"source": "REFERENCES_TAG"
}
]
}