High
python-markdown2 — security advisory
A Regular-Expression Denial of Service (ReDoS) in the Markdown2. extract_metadata() function (lib/markdown2.py) of trentm markdown2 through v2.5.5 allows attackers to cause a Denial of Service (DoS) via a crafted Markdown document.
- Products
- python-markdown2
- Affected versions
- 2.4.1-1, 2.4.11-1, 2.5.3-1~exp1, 2.5.4-1, 2.5.4-2, 2.5.4-3, 2.5.4-4
- Fixed versions
- Not specified
- CVEs
- CVE-2026-88753
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 01:24 UTC · Revision 1
Source evidence
A Regular-Expression Denial of Service (ReDoS) in the Markdown2. extract_metadata() function (lib/markdown2.py) of trentm markdown2 through v2.5.5 allows attackers to cause a Denial of Service (DoS) via a crafted Markdown document.
osv:DEBIAN-CVE-2026-88753
python-markdown2
Fixed versions: Not specified
python-markdown2
Fixed versions: Not specified
python-markdown2
Fixed versions: Not specified
Complete source record
{
"id": "10f22f06e1739c045224d65b6c8e9911576f6448f5cd02a564b10ac9cd2bb9a9",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-88753",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-88753",
"summary": "A Regular-Expression Denial of Service (ReDoS) in the Markdown2. extract_metadata() function (lib/markdown2.py) of trentm markdown2 through v2.5.5 allows attackers to cause a Denial of Service (DoS) via a crafted Markdown document.",
"evidence": "osv:DEBIAN-CVE-2026-88753",
"products": [
{
"name": {
"value": "python-markdown2",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.4.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.4.11-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.5.3-1~exp1",
"evidence": "/affected/0/versions"
},
{
"value": "2.5.4-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.5.4-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.5.4-3",
"evidence": "/affected/0/versions"
},
{
"value": "2.5.4-4",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "python-markdown2",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.4.11-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.5.3-1~exp1",
"evidence": "/affected/1/versions"
},
{
"value": "2.5.4-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.5.4-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.5.4-3",
"evidence": "/affected/1/versions"
},
{
"value": "2.5.4-4",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
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"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.4.11-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.5.3-1~exp1",
"evidence": "/affected/2/versions"
},
{
"value": "2.5.4-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.5.4-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.5.4-3",
"evidence": "/affected/2/versions"
},
{
"value": "2.5.4-4",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-88753",
"aliases": [
"DEBIAN-CVE-2026-88753"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "python-markdown2",
"purl": "pkg:deb/debian/python-markdown2?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"2.4.1-1",
"2.4.11-1",
"2.5.3-1~exp1",
"2.5.4-1",
"2.5.4-2",
"2.5.4-3",
"2.5.4-4"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-88753.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "python-markdown2",
"purl": "pkg:deb/debian/python-markdown2?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"2.4.11-1",
"2.5.3-1~exp1",
"2.5.4-1",
"2.5.4-2",
"2.5.4-3",
"2.5.4-4"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-88753.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
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}
]
}
],
"package": {
"name": "python-markdown2",
"purl": "pkg:deb/debian/python-markdown2?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"2.4.11-1",
"2.5.3-1~exp1",
"2.5.4-1",
"2.5.4-2",
"2.5.4-3",
"2.5.4-4"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-88753.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-23T18:04:42.439492146Z",
"provider": "osv",
"upstream": [
"CVE-2026-88753"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-88753"
]
},
"related_cves": [
{
"value": "CVE-2026-88753",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 423631,
"published_at": "2026-10-15T16:18:22.887+00:00"
}