CVE-2026-59926
published 2026-07-08CVE-2026-59926: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, render_admonition() in src/mistune/directives/admonition.py concatenates the…
PriorityP426medium6.1CVSS 3.1
AVNACLPRNUIRSCCLILAN
EPSS
0.33%
25.7th percentile
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, render_admonition() in src/mistune/directives/admonition.py concatenates the Admonition directive :class: option into the HTML class attribute without escaping, allowing attribute injection and cross-site scripting even when HTMLRenderer escape mode is enabled. This issue is fixed in version 3.2.1.
Affected
27 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| lepture | mistune | < 3.2.1 | 3.2.1 |
| mistune_project | mistune | < 3.3.0 | 3.3.0 |
| mistune_project | mistune | >= 0 < 3.3.0 | 3.3.0 |
| 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
nvdv4.05.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vendor_redhat6.1MEDIUM
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Red Hat
mistune: Mistune: Cross-Site Scripting via unescaped HTML class attribute in Admonition directive
vendor_redhat·2026-07-08·CVSS 6.1
CVE-2026-59926 [MEDIUM] CWE-79 mistune: Mistune: Cross-Site Scripting via unescaped HTML class attribute in Admonition directive
mistune: Mistune: Cross-Site Scripting via unescaped HTML class attribute in Admonition directive
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, render_admonition() in src/mistune/directives/admonition.py concatenates the Admonition directive :class: option into the HTML class attribute without escaping, allowing attribute injection and cross-site scripting even when HTMLRenderer escape mode is enabled. This issue is fixed in version 3.2.1.
A flaw was found in Mistune, a Python Markdown parser. The `render_admonition()` function in the Admonition directive concatenates user-controlled input into the HTML class attribute without proper escaping. This vulnerability allows for attribute injection and Cross-Site Scripting (XSS) attacks, even when the HTMLRend
GHSA
Mistune: XSS via unescaped class option in Admonition directive
ghsa·2026-07-20
CVE-2026-59926 [MEDIUM] CWE-79 Mistune: XSS via unescaped class option in Admonition directive
Mistune: XSS via unescaped class option in Admonition directive
In `src/mistune/directives/admonition.py`, the `render_admonition()` function concatenates the `:class:` option directly into the HTML class attribute without escaping (lines 63-68).
This allows attribute injection and XSS even when `HTMLRenderer(escape=True)` is used.
The directive name parameter is safe (validated against whitelist), but the class option comes from raw user input.
No detection rules found.
No public exploits indexed.
2026-07-08
Published