Parse Server has a LiveQuery protected-field guard bypass via array-like logical operator value

Exploitation

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

CVSS 4.0

5.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-34595: 0.26% estimated exploitation activity in the next 30 days; percentile 17.96 (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 An authenticated user with find class-level permission can bypass the protectedFields class-level permission setting on LiveQuery subscriptions. By sending a subscription with a $or, $and, or $nor operator value as a plain object with numeric keys and a length property (an "array-like" object) instead of an array, the protected-field guard is bypassed. The subscription event firing acts as a binary oracle, allowing the attacker to infer whether a protected field matches a given test value. Patches The fix validates that $or, $and, and $nor operator values are arrays in the LiveQuery subscription handler, the query depth checker, and the protected-field guard. As defense in depth, the LiveQuery query evaluator also rejects non-array values for these operators. Workarounds There is no known workaround.

Published by the source

1 Apr 2026, 00:07 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-mmg8-87c5-jrc2

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-mmg8-87c5-jrc2

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# Patch Next advisory brief: CVE-2026-34595

Advisory: Parse Server has a LiveQuery protected-field guard bypass via array-like logical operator value
IDs: CVE-2026-34595, GHSA-mmg8-87c5-jrc2
Record: https://patchnext.com/advisories/cve-2026-34595 (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: Medium (CVSS 5.3)
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.16, 8.6.70. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm parse-server: affected >= 9.0.0, < 9.7.0-alpha.16; < 8.6.70; fixed in 9.7.0-alpha.16, 8.6.70

## 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-mmg8-87c5-jrc2 (OSV record GHSA-mmg8-87c5-jrc2 lists affected ranges: npm parse-server >=9.0.0 =0 <8.6.70 (fixed))
- Verified: https://github.com/advisories/GHSA-mmg8-87c5-jrc2 (GitHub-reviewed advisory GHSA-mmg8-87c5-jrc2 lists affected ranges: npm parse-server >=9.0.0 =0 <8.6.70)

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