CVE-2026-34363
Parse Server: LiveQuery protected field leak via shared mutable state across concurrent subscribers
- State
- Published
- Severity
- 8.2 High
- Published
- Mar 31, 2026
- Updated
- Mar 31, 2026
- Reserved
- Mar 27, 2026
Description
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.65 and 9.7.0-alpha.9, when multiple clients subscribe to the same class via LiveQuery, the event handlers process each subscriber concurrently using shared mutable objects. The sensitive data filter modifies these shared objects in-place, so when one subscriber's filter removes a protected field, subsequent subscribers may receive the already-filtered object. This can cause protected fields and authentication data to leak to clients that should not see them, or cause clients that should see the data to receive an incomplete object. Additionally, when an afterEvent Cloud Code trigger is registered, one subscriber's trigger modifications can leak to other subscribers through the same shared mutable state. Any Parse Server deployment using LiveQuery with protected fields or afterEvent triggers is affected when multiple clients subscribe to the same class. This issue has been patched in versions 8.6.65 and 9.7.0-alpha.9.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.2 High | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N | GitHub_M |
Weaknesses
- CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Affected Products
| Product | Versions |
|---|---|
parse-serverparse-community |
|
References
- https://github.com/parse-community/parse-server/security/advisories/GHSA-m983-v2ff-wq65
- https://github.com/parse-community/parse-server/pull/10330
- https://github.com/parse-community/parse-server/pull/10331
- https://github.com/parse-community/parse-server/commit/5834e29234593addaa0251a85f572ad4f376320b
- https://github.com/parse-community/parse-server/commit/776c71c3078e77d38c94937f463741793609d055
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