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CVE-2026-59926 (GCVE-0-2026-59926)
Vulnerability from cvelistv5 – Published: 2026-07-08 16:16 – Updated: 2026-07-08 19:40
VLAI
EPSS
VEX
Title
Mistune: XSS via unescaped class option in Admonition directive
Summary
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.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/lepture/mistune/security/advis… | x_refsource_CONFIRM |
| https://github.com/lepture/mistune/commit/a3cb6e5… | x_refsource_MISC |
| https://github.com/lepture/mistune/releases/tag/v3.2.1 | x_refsource_MISC |
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"metrics": [
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"id": "CVE-2026-59926",
"options": [
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"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-08T17:48:29.407727Z",
"version": "2.0.3"
},
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"providerMetadata": {
"dateUpdated": "2026-07-08T19:40:52.229Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "mistune",
"vendor": "lepture",
"versions": [
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"status": "affected",
"version": "\u003c 3.2.1"
}
]
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"value": "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."
}
],
"metrics": [
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"cvssV4_0": {
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"privilegesRequired": "NONE",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "LOW",
"subIntegrityImpact": "LOW",
"userInteraction": "PASSIVE",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "NONE",
"vulnConfidentialityImpact": "LOW",
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"problemTypes": [
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"descriptions": [
{
"cweId": "CWE-79",
"description": "CWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
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"references": [
{
"name": "https://github.com/lepture/mistune/security/advisories/GHSA-g97x-gvcm-x72h",
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"title": "Mistune: XSS via unescaped class option in Admonition directive"
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PYSEC-2026-2214
Vulnerability from pysec - Published: 2026-07-08 17:17 - Updated: 2026-07-13 05:49
VLAI
Details
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.
Severity
6.1 (Medium)
Impacted products
| Name | purl | mistune | pkg:pypi/mistune |
|---|
Aliases
{
"affected": [
{
"ecosystem_specific": {},
"package": {
"ecosystem": "PyPI",
"name": "mistune",
"purl": "pkg:pypi/mistune"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.3.0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.1.0",
"0.2.0",
"0.3.0",
"0.3.1",
"0.4",
"0.4.1",
"0.5",
"0.5.1",
"0.6",
"0.7",
"0.7.1",
"0.7.2",
"0.7.3",
"0.7.4",
"0.8",
"0.8.1",
"0.8.2",
"0.8.3",
"0.8.4",
"2.0.0",
"2.0.0a1",
"2.0.0a2",
"2.0.0a3",
"2.0.0a4",
"2.0.0a5",
"2.0.0a6",
"2.0.0rc1",
"2.0.1",
"2.0.2",
"2.0.3",
"2.0.4",
"2.0.5",
"2.1.0",
"3.0.0",
"3.0.0a1",
"3.0.0a2",
"3.0.0a3",
"3.0.0rc1",
"3.0.0rc2",
"3.0.0rc3",
"3.0.0rc4",
"3.0.0rc5",
"3.0.1",
"3.0.2",
"3.1.0",
"3.1.1",
"3.1.2",
"3.1.3",
"3.1.4",
"3.2.0",
"3.2.1"
]
}
],
"aliases": [
"CVE-2026-59926",
"GHSA-g97x-gvcm-x72h"
],
"details": "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.",
"id": "PYSEC-2026-2214",
"modified": "2026-07-13T05:49:57.717693Z",
"published": "2026-07-08T17:17:28.323Z",
"references": [
{
"type": "ADVISORY",
"url": "https://github.com/lepture/mistune/releases/tag/v3.2.1"
},
{
"type": "ADVISORY",
"url": "https://github.com/lepture/mistune/security/advisories/GHSA-g97x-gvcm-x72h"
},
{
"type": "FIX",
"url": "https://github.com/lepture/mistune/commit/a3cb6e5655308797e8be021d6c7b5bab13cbace2"
}
],
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}