Mistune before 3.3.0 Quadratic-Time DoS via Unmatched Brackets in Inline Parser
Mistune before 3.3.0 contains an algorithmic complexity vulnerability in the inline link parser that allows unauthenticated attackers to exhaust CPU by submitting long runs of unmatched '[' characters. Attackers can send small markdown payloads that trigger O(N^2) parse_link_text and parse_link_label probing, occupying rendering workers for 30+ seconds per 16 KB input.
CVE-2026-115352
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-2026-115352
mistune
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": "lepture",
"product": "mistune",
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "3.3.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "3.3.0",
"versionType": "semver"
}
],
"packageURL": "pkg:pypi/mistune",
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-115352
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #53237 · Revision 1
- Added to Heist Feed
- Publisher date