Medium
node-markdown-it — security advisory
markdown-it is a Markdown parser. Versions 14.1.1 and below contain a denial-of-service vulnerability when typographer: true is enabled, due to quadratic (O(n^2)) processing in the smartquotes rule. The issue stems from repeatedly modifying strings with replaceAt(), which performs O(n) slicing and concatenation per quote character. This can cause excessive CPU consumption when parsing quote-heavy, user-supplied markdown and may let attackers degrade or disrupt service availability. Although typographer is disabled by default, many production apps enable it for smart typography, making the issue relevant. This issue has been fixed in version 14.2.0.
- Products
- node-markdown-it
- Affected versions
- 10.0.0+dfsg-2, 10.0.0+dfsg-3, 10.0.0+dfsg-3.1, 10.0.0+dfsg-4, 10.0.0+dfsg-5, 10.0.0+dfsg-6, 22.2.3+dfsg+~12.2.3-2, 22.2.3+dfsg+~12.2.3-4, 22.2.3+dfsg+~12.2.3-5
- Fixed versions
- Not specified
- CVEs
- CVE-2026-48988
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:07 UTC · Revision 1
Source evidence
markdown-it is a Markdown parser. Versions 14.1.1 and below contain a denial-of-service vulnerability when typographer: true is enabled, due to quadratic (O(n^2)) processing in the smartquotes rule. The issue stems from repeatedly modifying strings with replaceAt(), which performs O(n) slicing and concatenation per quote character. This can cause excessive CPU consumption when parsing quote-heavy, user-supplied markdown and may let attackers degrade or disrupt service availability. Although typographer is disabled by default, many production apps enable it for smart typography, making the issue relevant. This issue has been fixed in version 14.2.0.
osv:UBUNTU-CVE-2026-48988
node-markdown-it
Fixed versions: Not specified
node-markdown-it
Fixed versions: Not specified
node-markdown-it
Fixed versions: Not specified
node-markdown-it
Fixed versions: Not specified
node-markdown-it
Fixed versions: Not specified
Complete source record
{
"id": "aa9fff7495f91c34a9b83765b622a3bceddacb34dbdafd9e16c1129f616004e0",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-48988",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-48988",
"summary": "markdown-it is a Markdown parser. Versions 14.1.1 and below contain a denial-of-service vulnerability when typographer: true is enabled, due to quadratic (O(n^2)) processing in the smartquotes rule. The issue stems from repeatedly modifying strings with replaceAt(), which performs O(n) slicing and concatenation per quote character. This can cause excessive CPU consumption when parsing quote-heavy, user-supplied markdown and may let attackers degrade or disrupt service availability. Although typographer is disabled by default, many production apps enable it for smart typography, making the issue relevant. This issue has been fixed in version 14.2.0.",
"evidence": "osv:UBUNTU-CVE-2026-48988",
"products": [
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"evidence": "/affected/0/versions"
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{
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"evidence": "/affected/0/versions"
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{
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{
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"evidence": "/affected/4/versions"
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],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2026-48988",
"aliases": [
"UBUNTU-CVE-2026-48988"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
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],
"package": {
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"purl": "pkg:deb/ubuntu/node-markdown-it?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
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"10.0.0+dfsg-3",
"10.0.0+dfsg-3.1",
"10.0.0+dfsg-4",
"10.0.0+dfsg-5",
"10.0.0+dfsg-6"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48988.json"
},
"ecosystem_specific": {
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"ecosystem": "Ubuntu:25.10"
},
"versions": [
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"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
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],
"modified": "2026-10-17T13:00:23.956565532Z",
"provider": "osv",
"upstream": [
"CVE-2026-48988"
],
"references": [
"https://ubuntu.com/security/CVE-2026-48988",
"https://www.cve.org/CVERecord?id=CVE-2026-48988",
"https://github.com/markdown-it/markdown-it/security/advisories/GHSA-6v5v-wf23-fmfq",
"https://github.com/markdown-it/markdown-it/commit/9ce2087562c45d1e5ddd9f76b990f4b3fbe040e5"
]
},
"related_cves": [
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"evidence": "/upstream"
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],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 360495,
"published_at": "2026-06-17T21:16:00+00:00"
}