Description
Mistune before 3.3.0 contains an inefficient algorithmic complexity vulnerability in parse_link_text that allows remote attackers to cause denial of service through unbalanced square brackets. Attackers can submit markdown containing long runs of unmatched brackets to mistune.html(), triggering repeated forward scans that stall worker processes for minutes.
Published: 2026-10-22
Score: 8.7 High
EPSS: n/a
KEV: No
AI Analysis

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Remediation

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Tracking

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Advisories

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History

Fri, 23 Oct 2026 00:45:00 +0000

Type Values Removed Values Added
Description Mistune before 3.3.0 contains an inefficient algorithmic complexity vulnerability in parse_link_text that allows remote attackers to cause denial of service through unbalanced square brackets. Attackers can submit markdown containing long runs of unmatched brackets to mistune.html(), triggering repeated forward scans that stall worker processes for minutes.
Title Mistune before 3.3.0 Quadratic Denial of Service via parse_link_text
First Time appeared Mistune Project
Mistune Project mistune
Weaknesses CWE-407
CPEs cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*
Vendors & Products Mistune Project
Mistune Project mistune
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': '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'}


Subscriptions

Mistune Project Mistune
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-22T19:13:24.689Z

Reserved: 2026-10-22T11:20:02.626Z

Link: CVE-2026-115347

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-22T19:17:40.267

Modified: 2026-10-22T19:17:40.387

Link: CVE-2026-115347

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-23T03:30:15Z

Weaknesses
  • CWE-407

    Inefficient Algorithmic Complexity