Description
Mistune from 3.0.0 before 3.3.0 contains an algorithmic complexity denial of service vulnerability in the parse_link_text function in src/mistune/helpers.py. Attackers can submit markdown with deeply nested square brackets triggering quadratic parsing time, exhausting server CPU with small crafted requests.
Published: 2026-10-22
Score: 8.7 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Fri, 23 Oct 2026 04:30:00 +0000

Type Values Removed Values Added
First Time appeared Lepture
Lepture mistune
Vendors & Products Lepture
Lepture mistune

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

Type Values Removed Values Added
Description Mistune from 3.0.0 before 3.3.0 contains an algorithmic complexity denial of service vulnerability in the parse_link_text function in src/mistune/helpers.py. Attackers can submit markdown with deeply nested square brackets triggering quadratic parsing time, exhausting server CPU with small crafted requests.
Title Mistune 3.0.0 before 3.3.0 Denial of Service via Nested Bracket Parsing
First Time appeared Mistune Project
Mistune Project mistune
Weaknesses CWE-1333
CWE-606
CPEs cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*
Vendors & Products Mistune Project
Mistune Project mistune
References
Metrics threat_severity

None

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'}

threat_severity

Important


Subscriptions

Lepture Mistune
Mistune Project Mistune
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-22T19:13:26.171Z

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

Link: CVE-2026-115349

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-22T19:17:40.597

Modified: 2026-10-22T19:17:40.723

Link: CVE-2026-115349

cve-icon Redhat

Severity : Important

Publid Date: 2026-10-22T19:13:26Z

Links: CVE-2026-115349 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-23T04:15:18Z

Weaknesses