What is CVE-2026-32878?

CVE-2026-32878 is a high-severity vulnerability in Parse-Community Parse-Server, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 7.5/10. Published 2026-03-18.

How severe is CVE-2026-32878?

High severity. CVSS v3 base score is 7.5 out of 10.

Prototype Pollution in Parse-Community Parse-Server

CVE-2026-32878

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.6.0-alpha.20 and 8.6.44, 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. In 9.6.0-alpha.20 and 8.6.44, 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. No known workarounds are available.

Vulnerability class: Prototype Pollution

Published 2026-03-18 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.005 (38.1th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 38.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.001

Affected products

Parse-Community Parse-Server — versions >= 9.0.0, < 9.6.0-alpha.20, < 8.6.44
Parseplatform Parse-Server — versions 9.6.0

Weakness classification (CWE)

CWE-1321 — Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution)

References

github.com/parse-community/parse-server/security/advisories/GHSA-9ccr-fpp6-78qf (Vendor Advisory)
github.com/parse-community/parse-server/pull/10200 (Issue Tracking)
github.com/parse-community/parse-server/pull/10201 (Issue Tracking)

Frequently asked questions

What is CVE-2026-32878?: CVE-2026-32878 is a high-severity vulnerability in Parse-Community Parse-Server, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 7.5/10. Published 2026-03-18.
How severe is CVE-2026-32878?: High severity. CVSS v3 base score is 7.5 out of 10.