CVE-2026-44897
published 2026-05-26CVE-2026-44897: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening tag by string-concatenating the id…
PriorityP429medium6.1CVSS 3.1
AVNACLPRNUIRSCCLILAN
EPSS
0.23%
13.6th percentile
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening tag by string-concatenating the id attribute value directly into the HTML — with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character " in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element. This vulnerability is fixed in 3.2.1.
Affected
26 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| lepture | mistune | < 3.2.1 | 3.2.1 |
| mistune_project | mistune | < 3.2.1 | 3.2.1 |
| mistune_project | mistune | >= 0 < 3.2.1 | 3.2.1 |
| mta | mta-solution-server-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-datascience-cpu-py312-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-minimal-cpu-py312-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-pytorch-cuda-py312-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-pytorch-llmcompressor-cuda-py312-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-pytorch-rocm-py312-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-tensorflow-cuda-py312-rhel9 | — | — |
| rhoai | odh-pipeline-runtime-tensorflow-rocm-py312-rhel9 | — | — |
| rhoai | odh-th06-cpu-torch210-py312-rhel9 | — | — |
| rhoai | odh-th06-cpu-torch291-py312-rhel9 | — | — |
| rhoai | odh-th06-cuda130-torch210-py312-rhel9 | — | — |
| rhoai | odh-th06-cuda130-torch291-py312-rhel9 | — | — |
| rhoai | odh-th06-rocm64-torch291-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-datascience-cpu-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-minimal-cpu-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-minimal-cuda-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-minimal-rocm-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-pytorch-cuda-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-pytorch-rocm-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-tensorflow-cuda-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-tensorflow-rocm-py312-rhel9 | — | — |
CVSS provenance
nvdv3.16.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
vendor_redhat6.1MEDIUM
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Red Hat
mistune: Mistune: Cross-site scripting (XSS) via improper sanitization of HTML heading ID attribute
vendor_redhat·2026-05-26·CVSS 6.1
CVE-2026-44897 [MEDIUM] CWE-79 mistune: Mistune: Cross-site scripting (XSS) via improper sanitization of HTML heading ID attribute
mistune: Mistune: Cross-site scripting (XSS) via improper sanitization of HTML heading ID attribute
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening tag by string-concatenating the id attribute value directly into the HTML — with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character " in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element. This vulnerability is fixed in 3.2.1.
A flaw was found in Mistune, a Python Markdown parser. A remote attacker could exploit this vulnerability by providing specially crafted input to the HTMLRenderer.heading() function. This inp
VulDB
lepture mistune up to 3.2.0 Python Markdown Parser HTMLRenderer.heading ID cross site scripting (GHSA-v87v-83h2-53w7)
vuldb·2026-05-26·CVSS 6.1
CVE-2026-44897 [MEDIUM] lepture mistune up to 3.2.0 Python Markdown Parser HTMLRenderer.heading ID cross site scripting (GHSA-v87v-83h2-53w7)
A vulnerability has been found in lepture mistune up to 3.2.0 and classified as problematic. This issue affects the function HTMLRenderer.heading of the component Python Markdown Parser. This manipulation of the argument ID causes cross site scripting.
The identification of this vulnerability is CVE-2026-44897. It is possible to initiate the attack remotely. There is no exploit available.
The affected component should be upgraded.
GHSA
Mistune Heading ID Attribute has Injection XSS
ghsa·2026-05-09
CVE-2026-44897 [MEDIUM] CWE-79 Mistune Heading ID Attribute has Injection XSS
Mistune Heading ID Attribute has Injection XSS
## Summary
`HTMLRenderer.heading()` builds the opening `` tag by string-concatenating the `id` attribute value directly into the HTML — with no call to `escape()`, `safe_entity()`, or any other sanitisation function. A double-quote character `"` in the `id` value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, `src=`, `href=`, etc.) into the heading element.
The default TOC hook assigns safe auto-incremented IDs (`toc_1`, `toc_2`, …) that never contain user text. However, the `add_toc_hook()` API accepts a caller-supplied `heading_id` callback. Deriving heading IDs from the heading text itself — to produce human-readable slug anchors like `#installation` or `#getting-started` — is by
No detection rules found.
No public exploits indexed.
2026-05-26
Published