critical9.9

CVE-2026-30965

Parse Server vulnerable to session token exfiltration via `redirectClassNameForKey` query parameter

Impact

### Impact A vulnerability in Parse Server's query handling allows an authenticated or unauthenticated attacker to exfiltrate session tokens of other users by exploiting the `redirectClassNameForKey` query parameter. Exfiltrated session tokens can be used to take over user accounts. The vulnerability requires the attacker to be able to create or update an object with a new relation field, which depends on the Class-Level Permissions of at least one class. ### Patches The fix applies the same security checks that normally protect class access after the query redirect, ensuring that queries redirected via `redirectClassNameForKey` are subject to the same restrictions as direct queries to the target class. ### Workarounds Set restrictive Class-Level Permissions to prevent clients from creating new fields on classes, specifically by disabling `addField` for public access and unauthenticated users. Note that this limits client functionality and does not fully eliminate the risk if a relation field pointing to a protected class already exists in the schema. ### References - GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-6r2j-cxgf-495f - Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.2-alpha.8 - Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.21

Affected packages

Ecosystem	Package	Affected	Fixed in
npm	`parse-server`	>= 9.0.0-alpha.1, < 9.5.2-alpha.8	9.5.2-alpha.8

Affected products

Vendor	Product	Affected versions
Parseplatform	Parse-Server	before 8.6.21 from 9.0.0 before 9.5.2 Version 9.5.2

Weakness classification

CWE-863