CVE-2024-56510 is a medium-severity (CVSS 5.3) Cross-site Scripting (XSS) vulnerability in @marp-team/marp-core. A fix is available for @marp-team/marp-core — see the affected versions and patch details below.
Marp Core allows XSS by improper neutralization of HTML sanitization
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-56510.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2024-56510 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@marp-team/marp-corenpmDescription
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @marp-team/marp-core | ≥ 3.0.2&&< 3.9.1 | 3.9.1npm install @marp-team/marp-core@3.9.1 |
| 📦npm | @marp-team/marp-core | ≥ 4.0.0&&< 4.0.1 | 4.0.1npm install @marp-team/marp-core@4.0.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @marp-team/marp-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @marp-team/marp-core to 3.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-56510 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-56510 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-56510. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-56510 in your dependencies?
O3 Security finds CVE-2024-56510 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.