CVE-2026-76098

Mistune has Denial of Service — RecursionError via Excessive Emphasis Markers in Markdown

State
Published
Severity
7.5 High
Published
Aug 24, 2026
Updated
Aug 24, 2026
Reserved
Aug 18, 2026

Read the record on cve.org

Description

Mistune is a Python Markdown parser with renderers and plugins. Versions 3.3.0 through 3.3.2 are vulnerable to DoS through deeply nested tokens. HTML rendering creates deeply nested emphasis tokens from consecutive asterisk characters, and recursive rendering in HTMLRenderer.render_token() can exceed Python's recursion limit and raise RecursionError, allowing crafted Markdown to crash a parsing process. This issue is fixed in version 3.3.3

Scores

CVSSScoreVectorSource
3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HGitHub_M

Weaknesses

Affected Products

ProductVersions
mistunelepture
  • >= 3.3.0, < 3.3.3Affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.