CVE-2026-44897 (GCVE-0-2026-44897)
Vulnerability from cvelistv5
Published
2026-05-26 20:40
Modified
2026-06-01 17:09
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Summary
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.
References
| URL | Tags | |||||||
|---|---|---|---|---|---|---|---|---|
|
||||||||
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"containers": {
"adp": [
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"metrics": [
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"content": {
"id": "CVE-2026-44897",
"options": [
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"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-06-01T17:04:08.778886Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
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"providerMetadata": {
"dateUpdated": "2026-06-01T17:09:12.432Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
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],
"cna": {
"affected": [
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"product": "mistune",
"vendor": "lepture",
"versions": [
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"descriptions": [
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"value": "Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening \u003chN\u003e 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."
}
],
"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"
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}
],
"problemTypes": [
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"descriptions": [
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"cweId": "CWE-79",
"description": "CWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
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"type": "CWE"
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"providerMetadata": {
"dateUpdated": "2026-05-26T20:40:42.290Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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"references": [
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"name": "https://github.com/lepture/mistune/security/advisories/GHSA-v87v-83h2-53w7",
"tags": [
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"url": "https://github.com/lepture/mistune/security/advisories/GHSA-v87v-83h2-53w7"
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"name": "https://github.com/lepture/mistune/releases/tag/v3.2.1",
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"url": "https://github.com/lepture/mistune/releases/tag/v3.2.1"
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],
"source": {
"advisory": "GHSA-v87v-83h2-53w7",
"discovery": "UNKNOWN"
},
"title": "Mistune Heading ID Attribute Injection XSS"
}
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"assignerShortName": "GitHub_M",
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"datePublished": "2026-05-26T20:40:42.290Z",
"dateReserved": "2026-05-07T21:50:33.546Z",
"dateUpdated": "2026-06-01T17:09:12.432Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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