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

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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 (CVE-2026-76098)

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2026-2148 advisory.

    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 (CVE-2026-76098)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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 (CVE-2026-76098)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
455547	Echo: mistune: security update to 3.3.3	Tenable Cloud Security	Echo Local Security Checks	Local	high
455547	Echo: mistune: security update to 3.3.3	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
345788	Amazon Linux 2023 : python3-mistune (ALAS2023-2026-2148)	Nessus	Amazon Linux Local Security Checks	Local	high
339529	Linux Distros Unpatched Vulnerability : CVE-2026-76098	Nessus	Misc.	Local	high

Detections

Analytics

CVE-2026-76098

high

Tenable Plugins

high

high

high

high