league/commonmark before 2.9.1 Denial of Service via parsing
league/commonmark versions before 2.9.1 contain multiple denial of service vulnerabilities in fenced code block detection, reference link label lookup, and emphasis delimiter processing that perform super-linear work on crafted input. Attackers can submit specially crafted Markdown with long backtick runs, nested brackets, or delimiter sequences to consume disproportionate CPU time and prevent legitimate requests from completing.
CVE-2026-86430
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-86430
commonmark
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "thephpleague",
"product": "commonmark",
"versions": [
{
"status": "affected",
"version": "0.6.0",
"lessThan": "2.9.1",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "2.9.1",
"versionType": "semver"
}
],
"packageURL": "pkg:composer/league/commonmark",
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-86430
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #12947 · Revision 1
- Added to Heist Feed
- Publisher date