Regular Expression Denial of Service in HandlebarsGHSA-62gr-4qp9-h98f
HIGHFix: handlebars-lang/handlebars.js@8d5530eGHSA-62gr-4qp9-h98f is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in handlebars. A fix is available for handlebars — see the affected versions and patch details below.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-62gr-4qp9-h98f by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
handlebarsnpmDescription
Handlebars before 4.4.5 allows Regular Expression Denial of Service (ReDoS) because of eager matching. The parser may be forced into an endless loop while processing crafted templates. This may allow attackers to exhaust system resources.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | handlebars | ≥ 4.0.0&&< 4.4.5 | 4.4.5npm install handlebars@4.4.5 |
Affected Products
handlebarshandlebarsjsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for handlebars, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update handlebars to 4.4.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-62gr-4qp9-h98f is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat Quay includes Handlebars.js as a development dependency. It does not use Handlebars.js at runtime to process templates, so it has been given a low impact rating. Red Hat Virtualization includes Handlebars.js in two components. In ovirt-engine-ui-extentions, the version used is newer and not affected by this…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift Container Platform 4.6 | openshift4/ose-logging-kibana6:v4.6.0-202106181629.p0.git.40f3e72 | RHSA-2021:2500 |
| Red Hat Quay 3 | quay/quay-rhel8:v3.6.0-62 | RHSA-2021:3917 |
| Red Hat Virtualization Engine 4.4 | ovirt-web-ui-0:1.6.5-1.el8ev | RHSA-2020:5179 |
| RHPAM 7.13.1 async | handlebars | RHSA-2023:1334 |
Frequently Asked Questions
Is GHSA-62gr-4qp9-h98f in your dependencies?
Find it across npm, including transitive dependencies.