thlorenz browserify-shim vulnerable to prototype pollutionGHSA-866w-wm4h-95c6
CRITICALFix: thlorenz/browserify-shim#246GHSA-866w-wm4h-95c6 is a critical-severity (CVSS 9.8) CWE-1321 vulnerability in browserify-shim. 2 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for browserify-shim — 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
Where this sits among everything scored
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.
browserify-shimnpmDescription
Prototype pollution vulnerability in function resolveShims in resolve-shims.js in thlorenz browserify-shim 3.8.15 via the k variable in resolve-shims.js.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | browserify-shim | all versions | 3.8.16npm install browserify-shim@3.8.16 |
Affected Products
browserify-shimbrowserify-shim_projectResearch 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 browserify-shim, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update browserify-shim to 3.8.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-866w-wm4h-95c6 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.
Frequently Asked Questions
Is GHSA-866w-wm4h-95c6 in your dependencies?
Find it across npm, including transitive dependencies.