CVE-2026-33863
CVE-2026-33863 is a remote code execution vulnerability in convict. O3 Security confirms whether CVE-2026-33863 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Convict has prototype pollution via load(), loadFile(), and schema initialization
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.
convictnpmDescription
Impact
Two unguarded prototype pollution paths exist, not covered by previous fixes:
config.load()/config.loadFile()—overlay()recursively merges config data without checking for forbidden keys. Input containing__proto__orconstructor.prototype(e.g. from a JSON file) causes the recursion to reachObject.prototypeand write attacker-controlled values onto it.- Schema initialization — passing a schema with
constructor.prototype.*keys toconvict({...})causes default-value propagation to write directly toObject.prototypeat startup.
Depending on how polluted properties are consumed, impact ranges from unexpected behavior to authentication bypass or RCE.
Workarounds
Do not pass untrusted data to load(), loadFile(), or convict().
Resources
Prior advisory: GHSA-44fc-8fm5-q62h Related issue: https://github.com/mozilla/node-convict/issues/423
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | convict | all versions | 6.2.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for convict. 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 convict to 6.2.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33863 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 CVE-2026-33863 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-2026-33863. 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-2026-33863 in your dependencies?
O3 detects CVE-2026-33863 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.