How severe is GHSA-g97x-gvcm-x72h?

No CVSS score has been assigned to GHSA-g97x-gvcm-x72h yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-g97x-gvcm-x72h?

GHSA-g97x-gvcm-x72h affects the following packages: mistune (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-g97x-gvcm-x72h?

Update mistune to 3.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g97x-gvcm-x72h is resolved across your whole dependency graph.

How do I detect GHSA-g97x-gvcm-x72h in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mistune. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-g97x-gvcm-x72h if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-g97x-gvcm-x72h?

O3 pinpoints whether GHSA-g97x-gvcm-x72h is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-g97x-gvcm-x72h actively exploited in the wild?

No public exploit code has been indexed for GHSA-g97x-gvcm-x72h yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What type of vulnerability is GHSA-g97x-gvcm-x72h?

GHSA-g97x-gvcm-x72h is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-g97x-gvcm-x72h published, and has it been updated?

GHSA-g97x-gvcm-x72h was published on July 20, 2026 and was last updated on July 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

GHSA-g97x-gvcm-x72h

Mistune: XSS via unescaped class option in Admonition directive

Also known asCVE-2026-59926PYSEC-2026-2214

Published

Jul 20, 2026

Updated

Jul 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

1 pkg affected

🐍mistune

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`mistune`	all versions	3.3.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mistune. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update mistune to 3.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g97x-gvcm-x72h is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-g97x-gvcm-x72h is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-g97x-gvcm-x72h. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

Is GHSA-g97x-gvcm-x72h in your dependencies?

O3 detects GHSA-g97x-gvcm-x72h across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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