Parse Server vulnerable to schema poisoning via prototype pollution in deep copy

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:N/VI:L/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-32878: 0.36% estimated exploitation activity in the next 30 days; percentile 29.52 (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 attacker can bypass the default request keyword denylist protection and the class-level permission for adding fields by sending a crafted request that exploits prototype pollution in the deep copy mechanism. This allows injecting fields into class schemas that have field addition locked down, and can cause permanent schema type conflicts that cannot be resolved even with the master key. Patches The vulnerable third-party deep copy library has been replaced with a built-in deep clone mechanism that handles prototype properties safely, allowing the existing denylist check to correctly detect and reject the prohibited keyword. Workarounds None. Vulnerability Independence This vulnerability is not caused by or dependent on a vulnerability in a third-party dependency. The third-party deepcopy library that was replaced in the fix has no known CVE or security advisory regarding this. The library functions as designed. It is not vulnerable. The vulnerability is in parse-server's…

Published by the source

17 Mar 2026, 18:37 UTC

Last modified by the source

20 Mar 2026, 12:26 UTC

Source last checked

26 Oct 2026, 12:46 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-9ccr-fpp6-78qf

2. Revision 2 · amended · 24 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-9ccr-fpp6-78qf

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# Patch Next advisory brief: CVE-2026-32878

Advisory: Parse Server vulnerable to schema poisoning via prototype pollution in deep copy
IDs: CVE-2026-32878, GHSA-9ccr-fpp6-78qf
Record: https://patchnext.com/advisories/cve-2026-32878 (revision 3, source checked 26 Oct 2026, 12:46 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 9.6.0-alpha.20, 8.6.44. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm parse-server: affected >= 9.0.0, < 9.6.0-alpha.20; < 8.6.44; fixed in 8.6.44, 9.6.0-alpha.20

## 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-9ccr-fpp6-78qf (OSV record GHSA-9ccr-fpp6-78qf lists affected ranges: npm parse-server >=9.0.0 =0 <8.6.44 (fixed))
- Verified: https://github.com/advisories/GHSA-9ccr-fpp6-78qf (GitHub-reviewed advisory GHSA-9ccr-fpp6-78qf lists affected ranges: npm parse-server >=9.0.0 =0 <8.6.44)

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