GHSA-3cqr-58rm-57f8
HIGHGHSA-3cqr-58rm-57f8 is a high-severity (CVSS 8.1) remote code execution vulnerability in handlebars. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-3cqr-58rm-57f8 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Arbitrary Code Execution in Handlebars
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
handlebarsnpmDescription
Handlebars before 3.0.8 and 4.x before 4.5.3 is vulnerable to Arbitrary Code Execution. The lookup helper fails to properly validate templates, allowing attackers to submit templates that execute arbitrary JavaScript. This can be used to run arbitrary code on a server processing Handlebars templates or in a victim's browser (effectively serving as XSS).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | handlebars | all versions | 3.0.8 |
| 📦npm | handlebars | ≥ 4.0.0&&< 4.5.3 | 4.5.3 |
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 handlebars. 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 handlebars to 3.0.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3cqr-58rm-57f8 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-3cqr-58rm-57f8 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-3cqr-58rm-57f8. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-3cqr-58rm-57f8 in your dependencies?
O3 detects GHSA-3cqr-58rm-57f8 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.