CVE-2026-76098
published 2026-08-24CVE-2026-76098: 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…
PriorityP341high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
0.49%
41.9th percentile
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
Affected
30 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| lepture | mistune | — | — |
| mistune_project | mistune | >= 3.3.0 < 3.3.3 | 3.3.3 |
| mta | mta-solution-server-rhel9 | — | — |
| rhoai | odh-feature-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-th-torch-cpu-py312-rhel9 | — | — |
| rhoai | odh-th-torch-cuda-py312-rhel9 | — | — |
| rhoai | odh-th-torch-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-codeserver-datascience-cpu-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 | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vendor_redhat7.5HIGH
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GHSA
Mistune: Denial of Service — RecursionError via Excessive Emphasis Markers in Markdown
ghsa·2026-09-02
CVE-2026-76098 [HIGH] CWE-674 Mistune: Denial of Service — RecursionError via Excessive Emphasis Markers in Markdown
Mistune: Denial of Service — RecursionError via Excessive Emphasis Markers in Markdown
## Summary
Mistune v3.3.2 is vulnerable to a Denial of Service (DoS) attack via uncontrolled recursion in the HTML rendering of deeply-nested emphasis tokens. By submitting Markdown containing approximately 1,000 consecutive asterisk characters, an attacker causes the Python process to crash with RecursionError.
## Details
The InlineParser's _process_emphasis_delimiters() creates deeply nested tokens from consecutive emphasis markers (every 2 asterisks add one nesting level). With 1,000 consecutive asterisks, approximately 500 levels of nesting are produced. The HTMLRenderer.render_token() method (src/mistune/renderers/html.py:40-57) renders these tokens recursively: when a token has children, line 48
VulDB
Lepture Mistune up to 3.3.2 HTMLRenderer HTMLRenderer.render_token recursion
vuldb·2026-08-24·CVSS 7.5
CVE-2026-76098 [HIGH] Lepture Mistune up to 3.3.2 HTMLRenderer HTMLRenderer.render_token recursion
A vulnerability classified as problematic was found in Lepture Mistune up to 3.3.2. This affects the function HTMLRenderer.render_token of the component HTMLRenderer. Such manipulation leads to uncontrolled recursion.
This vulnerability is traded as CVE-2026-76098. The attack may be launched remotely. There is no exploit available.
Upgrading the affected component is advised.
Red Hat
mistune: Mistune: Denial of Service via excessive emphasis markers in Markdown
vendor_redhat·2026-08-24·CVSS 7.5
CVE-2026-76098 [HIGH] CWE-770 mistune: Mistune: Denial of Service via excessive emphasis markers in Markdown
mistune: Mistune: Denial of Service via excessive emphasis markers in Markdown
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
A flaw was found in Mistune, a Python Markdown parser. This vulnerability allows a remote attacker to trigger a Denial of Service (DoS) by submitting specially crafted Markdown input. The excessive use of emphasis markers, such as consecutive asterisks, creates deeply nested
No detection rules found.
No public exploits indexed.
2026-08-24
Published