HighFix available
php-league-commonmark — security advisory
The league/commonmark (thephpleague/commonmark) library in versions >= 1.5.0 and < 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment (they are not enabled by default and are excluded from the standard CommonMark and GitHub-Flavored Markdown converters), an unauthenticated attacker can submit small, specially crafted Markdown documents — such as text alternating with unpaired quotes, contiguous runs of block-level attribute blocks, or repeated class attributes — to trigger disproportionate CPU consumption and cause a denial of service. Fixed in 2.9.1.
- Products
- php-league-commonmark
- Affected versions
- 2.10.0-1, 2.10.1-1, 2.10.3-1, 2.3.9-1, 2.3.9-1+deb12u1, 2.4.0-1, 2.4.1-1, 2.4.2-1, 2.4.2-2, 2.5.0-1, 2.5.1-1, 2.5.3-1, 2.6.0-1, 2.6.1-1, 2.6.1-2, 2.6.2-1, 2.7.0-1, 2.7.0-1+deb13u1, 2.7.1-1, 2.7.1-2, 2.8.0-1, 2.8.1-1, 2.8.2-1, 2.8.2-2, 2.8.3-1, 2.9.0-1
- Fixed versions
- 2.10.0-1
- CVEs
- CVE-2026-86429
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 28 Oct 2026, 11:06 UTC · Revision 1
Source evidence
The league/commonmark (thephpleague/commonmark) library in versions >= 1.5.0 and < 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment (they are not enabled by default and are excluded from the standard CommonMark and GitHub-Flavored Markdown converters), an unauthenticated attacker can submit small, specially crafted Markdown documents — such as text alternating with unpaired quotes, contiguous runs of block-level attribute blocks, or repeated class attributes — to trigger disproportionate CPU consumption and cause a denial of service. Fixed in 2.9.1.
osv:DEBIAN-CVE-2026-86429
php-league-commonmark
Fixed versions: Not specified
php-league-commonmark
Fixed versions: Not specified
php-league-commonmark
Fixed versions: 2.10.0-1
Complete source record
{
"id": "e3731f1fe2e73af531a355a722268f66365394954f74fb0844d4b27054e5fd6c",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-86429",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-86429",
"summary": "The league/commonmark (thephpleague/commonmark) library in versions >= 1.5.0 and < 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment (they are not enabled by default and are excluded from the standard CommonMark and GitHub-Flavored Markdown converters), an unauthenticated attacker can submit small, specially crafted Markdown documents — such as text alternating with unpaired quotes, contiguous runs of block-level attribute blocks, or repeated class attributes — to trigger disproportionate CPU consumption and cause a denial of service. Fixed in 2.9.1.",
"evidence": "osv:DEBIAN-CVE-2026-86429",
"products": [
{
"name": {
"value": "php-league-commonmark",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.10.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.3.9-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.3.9-1+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "2.4.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.4.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.4.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.4.2-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.5.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.5.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.5.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.7.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.7.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.7.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.8.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.8.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.8.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.8.2-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.8.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.9.0-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "php-league-commonmark",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.10.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.10.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.10.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.7.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.7.0-1+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "2.7.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.7.1-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.8.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.8.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.8.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.8.2-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.8.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.9.0-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "php-league-commonmark",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.10.0-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "2.7.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.7.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.7.1-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.8.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.8.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.8.2-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.8.2-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.8.3-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.9.0-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-86429",
"aliases": [
"DEBIAN-CVE-2026-86429"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "php-league-commonmark",
"purl": "pkg:deb/debian/php-league-commonmark?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"2.10.0-1",
"2.10.1-1",
"2.10.3-1",
"2.3.9-1",
"2.3.9-1+deb12u1",
"2.4.0-1",
"2.4.1-1",
"2.4.2-1",
"2.4.2-2",
"2.5.0-1",
"2.5.1-1",
"2.5.3-1",
"2.6.0-1",
"2.6.1-1",
"2.6.1-2",
"2.6.2-1",
"2.7.0-1",
"2.7.1-1",
"2.7.1-2",
"2.8.0-1",
"2.8.1-1",
"2.8.2-1",
"2.8.2-2",
"2.8.3-1",
"2.9.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-86429.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "php-league-commonmark",
"purl": "pkg:deb/debian/php-league-commonmark?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"2.10.0-1",
"2.10.1-1",
"2.10.3-1",
"2.7.0-1",
"2.7.0-1+deb13u1",
"2.7.1-1",
"2.7.1-2",
"2.8.0-1",
"2.8.1-1",
"2.8.2-1",
"2.8.2-2",
"2.8.3-1",
"2.9.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-86429.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.10.0-1"
}
]
}
],
"package": {
"name": "php-league-commonmark",
"purl": "pkg:deb/debian/php-league-commonmark?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"2.7.0-1",
"2.7.1-1",
"2.7.1-2",
"2.8.0-1",
"2.8.1-1",
"2.8.2-1",
"2.8.2-2",
"2.8.3-1",
"2.9.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-86429.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-09T09:47:23.106159236Z",
"provider": "osv",
"upstream": [
"CVE-2026-86429"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-86429"
]
},
"related_cves": [
{
"value": "CVE-2026-86429",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 111426,
"published_at": "2026-09-07T13:20:42.18+00:00"
}