Headline
GHSA-x52f-h5g4-8qv5: Marp Core allows XSS by improper neutralization of HTML sanitization
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.
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.
Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.