GHSA-g97x-gvcm-x72h

Source

https://github.com/advisories/GHSA-g97x-gvcm-x72h

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-g97x-gvcm-x72h/GHSA-g97x-gvcm-x72h.json

JSON Data

https://api.test.osv.dev/v1/vulns/GHSA-g97x-gvcm-x72h

Aliases

Published

2026-07-20T21:34:14Z

Modified

2026-07-20T21:46:40Z

Severity

5.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N CVSS Calculator

Summary

Mistune: XSS via unescaped class option in Admonition directive

Details

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.

Database specific

{
    "cwe_ids":  [
        "CWE-79"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-07-20T21:34:14Z",
    "nvd_published_at":  "2026-07-08T17:17:28Z",
    "severity":  "MODERATE"
}

References

Affected packages

PyPI / mistune

Package

Name: mistune; View open source insights on deps.dev
Purl: pkg:pypi/mistune

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

3.3.0

Affected versions

0.*

0.1.0

0.2.0

0.3.0

0.3.1

0.4

0.4.1

0.5

0.5.1

0.6

0.7

0.7.1

0.7.2

0.7.3

0.7.4

0.8

0.8.1

0.8.2

0.8.3

0.8.4

2.*

2.0.0a1

2.0.0a2

2.0.0a3

2.0.0a4

2.0.0a5

2.0.0a6

2.0.0rc1

2.0.0

2.0.1

2.0.2

2.0.3

2.0.4

2.0.5

2.1.0

3.*

3.0.0a1

3.0.0a2

3.0.0a3

3.0.0rc1

3.0.0rc2

3.0.0rc3

3.0.0rc4

3.0.0rc5

3.0.0

3.0.1

3.0.2

3.1.0

3.1.1

3.1.2

3.1.3

3.1.4

3.2.0

3.2.1

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-g97x-gvcm-x72h/GHSA-g97x-gvcm-x72h.json"