GHSA-r5fr-rjxr-66jc is a high-severity (CVSS 8.1) Code Injection vulnerability in lodash. 6 public exploit references exist, so weaponization risk is real. O3 Security confirms whether GHSA-r5fr-rjxr-66jc is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
lodash vulnerable to Code Injection via `_.template` imports key names
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
GHSA-r5fr-rjxr-66jc 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 368,770 CVEs with a current EPSS score, this one falls in the 10–50% 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.
lodashnpmlodash-esnpmlodash.templatenpmDescription
Impact
The fix for CVE-2021-23337 added validation for the variable option in _.template but did not apply the same validation to options.imports key names. Both paths flow into the same Function() constructor sink.
When an application passes untrusted input as options.imports key names, an attacker can inject default-parameter expressions that execute arbitrary code at template compilation time.
Additionally, _.template uses assignInWith to merge imports, which enumerates inherited properties via for..in. If Object.prototype has been polluted by any other vector, the polluted keys are copied into the imports object and passed to Function().
Patches
Users should upgrade to version 4.18.0.
The fix applies two changes:
- Validate
importsKeysagainst the existingreForbiddenIdentifierCharsregex (same check already used for thevariableoption) - Replace
assignInWithwithassignWithwhen merging imports, so only own properties are enumerated
Workarounds
Do not pass untrusted input as key names in options.imports. Only use developer-controlled, static key names.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | lodash | ≥ 4.0.0&&< 4.18.0 | 4.18.0 |
| 📦npm | lodash-es | ≥ 4.0.0&&< 4.18.0 | 4.18.0 |
| 📦npm | lodash-amd | ≥ 4.0.0&&< 4.18.0 | 4.18.0 |
| 📦npm | lodash.template | ≥ 4.0.0&&< 4.18.0 | 4.18.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Lodash versions prior to 4.17.21 are vulnerable to Command Injection via…
Lodash versions prior to 4.17.21 are vulnerable to Command Injection via…
Lodash versions prior to 4.17.21 are vulnerable to Command Injection via…
Lodash versions prior to 4.17.21 are vulnerable to Command Injection via…
Lodash versions prior to 4.17.21 are vulnerable to Command Injection via…
Lodash versions prior to 4.17.21 are vulnerable to Command Injection via…
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for lodash. 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 lodash to 4.18.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-r5fr-rjxr-66jc 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-r5fr-rjxr-66jc 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-r5fr-rjxr-66jc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
In OpenShift ServiceMesh (OSSM) and Red Hat OpenShift Jaeger (RHOSJ) the affected containers are behind OpenShift OAuth authentication. This restricts access to the vulnerable nodejs-lodash library to authenticated users only, therefore the impact is low. While Red Hat Virtualization's cockpit-ovirt has a dependency…
Frequently Asked Questions
Is GHSA-r5fr-rjxr-66jc in your dependencies?
O3 detects GHSA-r5fr-rjxr-66jc across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.