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CVE-2026-115349

7.5, high

Mistune from 3.0.0 before 3.3.0 contains an algorithmic complexity denial of service vulnerability in the parse_link_text function in…

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
7.5, high high CVSS v3.1
EPSS, next 30 days
n/a
Exploitation
No public evidence
Published
22 Oct 2026yesterday

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.

Details

Vendor
Lepture
Product
mistune
Weakness
CWE-1333 (opens in a new tab)
Status
Deferred
Updated
22 Oct 2026
Assigner
disclosure@vulncheck.com

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References 2

Advisories 1

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Lepture CVEs

Every Lepture CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-115347 Mistune before 3.3.0 contains an inefficient algorithmic complexity vulnerability in parse_link_text that allows remote attackers to… 7.5, high
  • CVE-2026-115348 Lepture mistune Uncontrolled Resource Consumption Vulnerability 7.5, high
  • CVE-2026-115352 Mistune before 3.3.0 contains an algorithmic complexity vulnerability in the inline link parser that allows unauthenticated attackers to… 7.5, high
  • CVE-2026-115353 Lepture mistune Path Traversal Vulnerability 8.6, high
  • CVE-2026-115355 Lepture mistune Path Traversal Vulnerability 7.5, high

Beyond this page

Is CVE-2026-115349 in your network?

This page tells you how dangerous CVE-2026-115349 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 23 Oct 2026, not the live upstream state.