Inefficient Regular Expression Complexity Affecting mistune package, versions *


Severity

Recommended
low

Based on Debian security rating.

Threat Intelligence

EPSS
0.34% (28th percentile)

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  • Snyk IDSNYK-DEBIAN13-MISTUNE-21602951
  • published23 Oct 2026
  • disclosed22 Oct 2026

Introduced: 22 Oct 2026

NewCVE-2026-115349  (opens in a new tab)
CWE-1333  (opens in a new tab)

How to fix?

There is no fixed version for Debian:13 mistune.

NVD Description

Note: Versions mentioned in the description apply only to the upstream mistune package and not the mistune package as distributed by Debian. See How to fix? for Debian:13 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1