GHSA-x52f-h5g4-8qv5 Marp Core allows XSS by improper neutralization of HTML sanitization

• npm @marp-team/marp-core: >= 3.0.2, < 3.9.1 → fixed in 3.9.1 • npm @marp-team/marp-core: >= 4.0.0, < 4.0.1 → fixed in 4.0.1

Marp Core (`@marp-team/marp-core`) from v3.0.2 to v3.9.0 and v4.0.0, are vulnerable to cross-site scripting (XSS) due to improper neutralization of HTML sanitization. Impact Marp Core includes an HTML sanitizer with allowlist support. In the affected versions, the built-in allowlist is enabled by default. When the allowlist is active, if insufficient HTML comments are included, the sanitizer may fail to properly sanitize HTML content and lead cross-site scripting (XSS). Patches Marp Core v3.9.1 and v4.0.1 have been patched to fix that. Workarounds If you are unable to update the package immediately, disable all HTML tags by setting `html: false` option in the `Marp` class constructor. ```javascript const marp = new Marp({ html: false }) ``` References • CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') • https://github.com/marp-team/marp-core/pull/282 • https://github.com/marp-team/marp-core/commit/61a1def244d1b6faa8e2c0be97ec0b68cab3ab49 Credits Thanks to @Ry0taK for finding out this vulnerability.