Description
Mistune from 3.0.0 before 3.3.0 contains an algorithmic complexity vulnerability in the inline link parser's parse_link_text function that allows unauthenticated attackers to exhaust CPU with unbalanced brackets. Attackers can submit Markdown containing many unbalanced '[' or '![' characters, forcing repeated unbounded forward scans and tying up worker processes for minutes.
Published: 2026-10-22
Score: 8.7 High
EPSS: < 1% Very Low
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 12:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-606
References
Metrics threat_severity

None

threat_severity

Important


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 vulnerability in the inline link parser's parse_link_text function that allows unauthenticated attackers to exhaust CPU with unbalanced brackets. Attackers can submit Markdown containing many unbalanced '[' or '![' characters, forcing repeated unbounded forward scans and tying up worker processes for minutes.
Title Mistune before 3.3.0 Quadratic-Time DoS via parse_link_text
First Time appeared Mistune Project
Mistune Project mistune
Weaknesses CWE-400
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: 2026-10-22T19:13:25.416Z

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

Link: CVE-2026-115348

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-22T19:17:40.430

Modified: 2026-10-22T19:17:40.550

Link: CVE-2026-115348

cve-icon Redhat

Severity : Important

Publid Date: 2026-10-22T19:13:25Z

Links: CVE-2026-115348 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-23T13:30:07Z

Weaknesses
  • CWE-400

    Uncontrolled Resource Consumption

  • CWE-606

    Unchecked Input for Loop Condition