CVE-2026-32742: Parse Server session creation endpoint allows overwriting server-generated session fields

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-18 · updated 2026-06-17
Weakness: CWE-915

Description

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.17 and 8.6.42, an authenticated user can overwrite server-generated session fields (`sessionToken`, `expiresAt`, `createdWith`) when creating a session object via `POST /classes/_Session`. This allows bypassing the server's session expiration policy by setting an arbitrary far-future expiration date. It also allows setting a predictable session token value. Starting in version 9.6.0-alpha.17 and 8.6.42, the session creation endpoint filters out server-generated fields from user-supplied data, preventing them from being overwritten. As a workaround, add a `beforeSave` trigger on the `_Session` class to validate and reject or strip any user-supplied values for `sessionToken`, `expiresAt`, and `createdWith`.

Affected products

parse-community parse-server: before 8.6.42; from 9.0.0 before 9.6.0; 9.6.0-alpha1, 9.6.0-alpha10, 9.6.0-alpha11, 9.6.0-alpha12, 9.6.0-alpha13, 9.6.0-alpha14 (+9) — fixed in 8.6.42, 9.6.0

How to fix

Upgrade to a fixed version: parse-community parse-server 8.6.42, 9.6.0. Check the vendor advisory for mitigations.

References

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