CVE-2026-33163
Parse Server leaks protected fields via LiveQuery afterEvent trigger
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.
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
parse-servernpmDescription
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.6.0-alpha.35 and 8.6.50, when a Parse.Cloud.afterLiveQueryEvent trigger is registered for a class, the LiveQuery server leaks protected fields and authData to all subscribers of that class. Fields configured as protected via Class-Level Permissions (protectedFields) are included in LiveQuery event payloads for all event types (create, update, delete, enter, leave). Any user with sufficient CLP permissions to subscribe to the affected class can receive protected field data of other users, including sensitive personal information and OAuth tokens from third-party authentication providers. The vulnerability was caused by a reference detachment bug. When an afterEvent trigger is registered, the LiveQuery server converts the event object to a Parse.Object for the trigger, then creates a new JSON copy via toJSONwithObjects(). The sensitive data filter was applied to the Parse.Object reference, but the unfiltered JSON copy was sent to clients. The fix in versions 9.6.0-alpha.35 and 8.6.50 ensures that the JSON copy is assigned back to the response object before filtering, so the filter operates on the actual data sent to clients. As a workaround, remove all Parse.Cloud.afterLiveQueryEvent trigger registrations. Without an afterEvent trigger, the reference detachment does not occur and protected fields are correctly filtered.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | parse-server | ≥ 9.0.0&&< 9.6.0-alpha.35 | 9.6.0-alpha.35 |
| 📦npm | parse-server | all versions | 8.6.50 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for parse-server. 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 parse-server to 9.6.0-alpha.35 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33163 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-2026-33163 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-2026-33163. 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-2026-33163 in your dependencies?
O3 detects CVE-2026-33163 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.