Medium
Security advisory
Cure53 DOMPurify before 2.0.17 allows mutation XSS. This occurs because a serialize-parse roundtrip does not necessarily return the original DOM tree, and a namespace can change from HTML to MathML, as demonstrated by nesting of FORM elements.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2020-26870
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 11:09 UTC · Revision 1
Source evidence
Cure53 DOMPurify before 2.0.17 allows mutation XSS. This occurs because a serialize-parse roundtrip does not necessarily return the original DOM tree, and a namespace can change from HTML to MathML, as demonstrated by nesting of FORM elements.
osv:CVE-2020-26870
Complete source record
{
"id": "67e24b6b933a7e6ba6935126805724454dd54f6eee1833e0d513a256a8c92c27",
"url": "https://osv.dev/vulnerability/CVE-2020-26870",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2020-26870",
"summary": "Cure53 DOMPurify before 2.0.17 allows mutation XSS. This occurs because a serialize-parse roundtrip does not necessarily return the original DOM tree, and a namespace can change from HTML to MathML, as demonstrated by nesting of FORM elements.",
"evidence": "osv:CVE-2020-26870",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2020-26870",
"aliases": [
"CVE-2020-26870",
"GHSA-63q7-h895-m982"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/cure53/dompurify",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "f04574b5c1761ace5fa4c60f3e452c0c2eb02ff4"
},
{
"fixed": "02724b8eb048dd219d6725b05c3000936f11d62d"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:cure53:dompurify:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "2.0.17"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "02724b8eb048dd219d6725b05c3000936f11d62d"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"2.0.16",
"2.0.15",
"2.0.14",
"2.0.13",
"2.0.12",
"2.0.11",
"2.0.10",
"2.0.9",
"2.0.8",
"2.0.6",
"2.0.5",
"2.0.4",
"2.0.3",
"2.0.2",
"2.0.1",
"2.0.0",
"1.0.11",
"1.0.10",
"1.0.9",
"1.0.8",
"1.0.7",
"1.0.6",
"1.0.5",
"1.0.4",
"1.0.3",
"1.0.2",
"1.0.1",
"1.0.0",
"0.9.0",
"0.8.9",
"0.8.8",
"0.8.7",
"0.8.6",
"0.8.5",
"0.8.4",
"0.8.3",
"0.8.2",
"0.8.1",
"0.8.0",
"0.7.3",
"0.7.2",
"0.7.1",
"0.7.0",
"0.6.7",
"0.6.6",
"0.6.5",
"0.6.4",
"0.6.3",
"0.6.2",
"0.6.1",
"0.6.0",
"0.4.5",
"0.4.4",
"0.4.3",
"0.4.2",
"0.4",
"0.3",
"v0.3",
"0.1"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-26870.json"
}
}
],
"modified": "2026-10-20T10:52:58.617018534Z",
"provider": "osv",
"references": [
"https://lists.debian.org/debian-lts-announce/2020/10/msg00029.html",
"https://github.com/cure53/DOMPurify/commit/02724b8eb048dd219d6725b05c3000936f11d62d",
"https://github.com/cure53/DOMPurify/compare/2.0.16...2.0.17",
"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-26870",
"https://www.oracle.com//security-alerts/cpujul2021.html",
"https://research.securitum.com/mutation-xss-via-mathml-mutation-dompurify-2-0-17-bypass/"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:a:oracle:application_express:*:*:*:*:*:*:*:*"
],
"vendor_product": "oracle:application_express",
"extracted_events": [
{
"range": [
{
"fixed": "21.1.0.00.01"
}
],
"source": "CPE_RANGE"
}
]
},
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "9.0"
},
{
"last_affected": "9.0"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:a:microsoft:visual_studio_2017:15.9:*:*:*:*:*:*:*"
],
"vendor_product": "microsoft:visual_studio_2017",
"extracted_events": [
{
"range": [
{
"introduced": "15.9"
},
{
"last_affected": "15.9"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:a:microsoft:visual_studio_2019:16.0:*:*:*:*:*:*:*",
"cpe:2.3:a:microsoft:visual_studio_2019:16.4:*:*:*:*:*:*:*",
"cpe:2.3:a:microsoft:visual_studio_2019:16.7:*:*:*:*:*:*:*",
"cpe:2.3:a:microsoft:visual_studio_2019:16.8:*:*:*:*:*:*:*"
],
"vendor_product": "microsoft:visual_studio_2019",
"extracted_events": [
{
"range": [
{
"introduced": "16.0"
},
{
"last_affected": "16.0"
},
{
"introduced": "16.4"
},
{
"last_affected": "16.4"
},
{
"introduced": "16.7"
},
{
"last_affected": "16.7"
},
{
"introduced": "16.8"
},
{
"last_affected": "16.8"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2020-26870",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 384115,
"published_at": "2020-10-07T16:15:18.03+00:00"
}