LiveQuery protected field leak via shared mutable state across concurrent subscribers

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.2 · 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 · score source

EPSS

• CVE-2026-34363: 0.37% estimated exploitation activity in the next 30 days; percentile 31.34 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact 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. Patches The fix deep-clones the shared objects at the start of each subscriber's processing callback, ensuring each subscriber works on an…

Published by the source

30 Mar 2026, 17:40 UTC

Last modified by the source

6 Apr 2026, 15:27 UTC

Source last checked

26 Oct 2026, 12:47 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-m983-v2ff-wq65

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-m983-v2ff-wq65

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# Patch Next advisory brief: CVE-2026-34363

Advisory: LiveQuery protected field leak via shared mutable state across concurrent subscribers
IDs: CVE-2026-34363, GHSA-m983-v2ff-wq65
Record: https://patchnext.com/advisories/cve-2026-34363 (revision 3, source checked 26 Oct 2026, 12:47 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: parse-server 9.7.0-alpha.9, 8.6.65. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm parse-server: affected >= 9.0.0, < 9.7.0-alpha.9; < 8.6.65; fixed in 8.6.65, 9.7.0-alpha.9

## Suggested inspection (read-only)
- `npm ls parse-server --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on parse-server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-m983-v2ff-wq65 (OSV record GHSA-m983-v2ff-wq65 lists affected ranges: npm parse-server >=9.0.0 =0 <8.6.65 (fixed))
- Verified: https://github.com/advisories/GHSA-m983-v2ff-wq65 (GitHub-reviewed advisory GHSA-m983-v2ff-wq65 lists affected ranges: npm parse-server >=9.0.0 =0 <8.6.65)

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