Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the safe_url filter in src/mistune/renderers/html.py blocks only javascript:, vbscript:, file:, and data: schemes, allowing legacy or chained schemes such as feed:, view-source:, jar:, livescript:, mocha:, ms-its:, mk:, and res: to reach rendered href and src attributes and potentially execute script in affected user agents. This issue is fixed in version 3.3.0.
{
"cwe_ids": [
"CWE-184",
"CWE-79"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59929.json",
"cna_assigner": "GitHub_M"
}{
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "3.3.0"
}
],
"cpe": "cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*",
"source": [
"CPE_RANGE",
"REFERENCES"
]
}