CVE-2021-32818
MEDIUMCVE-2021-32818 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in haml-coffee. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2021-32818 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Insecure template handling in haml-coffee
Real-World Exposure
haml-coffeeReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
haml-coffee is a JavaScript templating solution. haml-coffee mixes pure template data with engine configuration options through the Express render API. More specifically, haml-coffee supports overriding a series of HTML helper functions through its configuration options. A vulnerable application that passes user controlled request objects to the haml-coffee template engine may introduce RCE vulnerabilities. Additionally control over the escapeHtml parameter through template configuration pollution ensures that haml-coffee would not sanitize template inputs that may result in reflected Cross Site Scripting attacks against downstream applications. There is currently no fix for these issues as of the publication of this CVE. The latest version of haml-coffee is currently 1.14.1. For complete details refer to the referenced GHSL-2021-025.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | haml-coffee | all versions | No fix |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for haml-coffee. 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.
Remediation status
No patched version of haml-coffee has shipped for CVE-2021-32818 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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 CVE-2021-32818 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 CVE-2021-32818. 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-2021-32818 in your dependencies?
O3 detects CVE-2021-32818 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.