Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, the Image directive plugin validates the :width: and :height: options with a regex compiled as _num_re = re.compile(r"^\d+(?:\.\d*)?"). When the validated value is not a plain integer, render_block_image() inserts it directly into a style="width:...;" or style="height:...;" attribute. Because the value was accepted by the prefix-only regex, any CSS after the leading digits reaches the style= attribute verbatim and without escaping. This vulnerability is fixed in 3.2.1.

An update of the python3 package has been released.

The remote SUSE Linux SLES16 / SLES_SAP16 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:21858-1 advisory.

    This update for python-mistune fixes the following issues

    - CVE-2026-33079: ReDoS in `LINK_TITLE_RE` can lead to denial of service via a crafted Markdown     (bsc#1264347).
    - CVE-2026-33441: processing of malformed reference links can lead to excessive resource consumption and     denial of       service (bsc#1264752).
    - CVE-2026-44708: improper HTML escaping in the math plugin can lead to XSS (bsc#1264751).
    - CVE-2026-44896: improper escaping in `render_figure` can lead to attribute injection and XSS     (bsc#1264754).
    - CVE-2026-44897: improper sanitization of user-controlled input in `HTMLRenderer.heading` can lead to XSS       (bsc#1264750).
    - CVE-2026-44898: improper sanitization of user-supplied HTML input in `render_toc_ul` can lead to XSS     (bsc#1265052).
    - CVE-2026-44899: improper input verification in Image directive plugin and improper escaping in     `render_block_image`       can lead to CSS injection (bsc#1265053).

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

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

The remote openSUSE 16 host has a package installed that is affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:20827-1 advisory.

    This update for python-mistune fixes the following issues

    - CVE-2026-33079: ReDoS in `LINK_TITLE_RE` can lead to denial of service via a crafted Markdown     (bsc#1264347).
    - CVE-2026-33441: processing of malformed reference links can lead to excessive resource consumption and     denial of       service (bsc#1264752).
    - CVE-2026-44708: improper HTML escaping in the math plugin can lead to XSS (bsc#1264751).
    - CVE-2026-44896: improper escaping in `render_figure` can lead to attribute injection and XSS     (bsc#1264754).
    - CVE-2026-44897: improper sanitization of user-controlled input in `HTMLRenderer.heading` can lead to XSS       (bsc#1264750).
    - CVE-2026-44898: improper sanitization of user-supplied HTML input in `render_toc_ul` can lead to XSS     (bsc#1265052).
    - CVE-2026-44899: improper input verification in Image directive plugin and improper escaping in     `render_block_image`       can lead to CSS injection (bsc#1265053).

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

Note that Nessus has not tested for these issues 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. Prior to 3.2.1, the Image directive plugin     validates the :width: and :height: options with a regex compiled as _num_re =     re.compile(r^\d+(?:\.\d*)?). When the validated value is not a plain integer, render_block_image()     inserts it directly into a style=width:...; or style=height:...; attribute. Because the value was     accepted by the prefix-only regex, any CSS after the leading digits reaches the style= attribute verbatim     and without escaping. This vulnerability is fixed in 3.2.1. (CVE-2026-44899)

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

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. Prior to 3.2.1, the Image directive plugin
    validates the :width: and :height: options with a regex compiled as _num_re =
    re.compile(r"^\d+(?:\.\d*)?"). When the validated value is not a plain integer, render_block_image()
    inserts it directly into a style="width:...;" or style="height:...;" attribute. Because the value was
    accepted by the prefix-only regex, any CSS after the leading digits reaches the style= attribute verbatim
    and without escaping. This vulnerability is fixed in 3.2.1. (CVE-2026-44899)

ID	Name	Product	Family	Type	Severity
332604	Photon OS 5.0: Python3 PHSA-2026-5.0-91-0911	Nessus	PhotonOS Local Security Checks	Local	high
332506	Photon OS 5.0: Python3 PHSA-2026-5.0-92-0911	Nessus	PhotonOS Local Security Checks	Local	high
324560	Photon OS 5.0: Python3 PHSA-2026-5.0-0911	Nessus	PhotonOS Local Security Checks	Local	high
318185	SUSE SLES16 Security Update : python-mistune (SUSE-SU-2026:21858-1)	Nessus	SuSE Local Security Checks	Local	high
318089	openSUSE 16 Security Update : python-mistune (openSUSE-SU-2026:20827-1)	Nessus	SuSE Local Security Checks	Local	high
317300	Linux Distros Unpatched Vulnerability : CVE-2026-44899	Nessus	Misc.	Local	medium
441851	SCA: security update for mistune (GHSA-ccfx-mfmx-2fx9)	Tenable Cloud Security	SCA Checks	Local	medium
441851	SCA: security update for mistune (GHSA-ccfx-mfmx-2fx9)	Tenable Self-Hosted Container Security	SCA Checks	Local	medium

Detections

Analytics

CVE-2026-44899

medium

Tenable Plugins

high

high

high

high

high

medium

medium

medium